Methodology

Every rule here is compiled from documents we can point to. Where a manufacturer publishes its own dating material, that document carries a rule on its own: a company describing the numbers it stamped needs no second voice.

Where a company doesn't document its numbering, a rule ships only with at least two corroborating sources, and at least one of them has to be documentary: manufacturer material, a factory document with a traceable chain of custody, or a brand specialist's published reference. Aggregated owner reports can corroborate a reading; they never carry one on their own. Editorial notes of our own corroborate nothing, and the data layer refuses to build a table that breaks any of this.

The tables here are compiled clean-room. Another site's tables, wording and layout stay off our pages. We re-derive which numbers map to which years from the sources themselves and write every rule into our own schema and our own sentences.

Sources and retrieval dates live inside the data file next to the rule they back, and the data file is what this site renders. Across 6 brands we cite 33 sources behind 49 serial formats: 12 manufacturer documents, 19 brand-specialist references, and 2 aggregated owner reports. Those are distinct documents: where two brands lean on the same article, it counts once. Full citations stay internal. What a page shows you is the date the data was last checked, the version of the rules that answered you, and the reasoning in plain English.

A reading carries no byline and no personal opinion. GearSerials is the author of every page, and every answer comes out of the published record. The decoder stops where that record stops: across the brands we cover, 15 eras are marked as ones we don't date, and a serial from one of them gets guidance instead of a year.

Every decoded claim on this site carries one of the levels below, alongside the date the data behind it was last checked.

definitiveOne year, from a published table

The manufacturer published a chart that maps this number to this year, and the number matches it cleanly. The company that issued the serial is the source of the year.

probableOne year, with a caveat we have to pass on

A single year, corroborated, but carrying a qualification the sources themselves state: a decal used long after the year it names, or a second product line numbered on a run that looks identical. The year is the answer and the meter is the hedge.

ambiguousA set of years, never collapsed into one

Where a prefix or a number block was reused, every year it can mean stays on the page. Next to them sits the question that separates them (what the headstock says, what the label inside the soundhole says), answered in the browser, with the ruled-out years left visible rather than deleted. Where nothing published separates the years, the page says so and they all stay.

undecodableWe recognize the number and decline to date it

Three situations end here: an era numbered in a way that can't be undone from the serial alone, a number newer than the records we've checked, and a number that matches no format we carry. Each gets the same treatment: what the number does tell us, what to examine on the instrument instead, and, for the last of the three, how many formats we walked for that brand before saying so.

The rules version is a content hash of that brand's data table. It moves when the data moves and at no other time, so the stamp on an answer, the version recorded against your feedback, and the row below always name the same rules.

• Martin Serials decoded 1898–2025 Data updated 24 August 2026· rules 51545f78
• Taylor Serials decoded 1993–present Data updated 24 August 2026· rules eb108dc8
• Fender Serials decoded 1976–present Data updated 1 September 2026· rules 1799eb70
• Gibson Serials decoded 1977–present Data updated 1 September 2026· rules b76c7352
• PRS Serials decoded 1985–present Data updated 28 August 2026· rules 156ccc1d
• Squier Serials decoded 1982–2012 Data updated 24 August 2026· rules d7a4bad1

If we have a number wrong, we want to hear it. Every result page ends with the question "Was this right?", and answering no opens one optional box for whatever you know that we don't: a date stamped inside the neck pocket, a label that contradicts the year, a prefix we've never seen. There's no account to make and nothing else to fill in.

When a reading changes as a result, it goes in the log below, in full, with what changed and why. The log is generated from the same data the decoder runs on, so an answer can't change without the change appearing here.

97 entries, newest first. Each one names the brand, the day it landed, and the versions on either side of it: the rule versions where the change was to a brand's records, the engine versions where it was to the code those records run through.

1. 1 September 2026 · Fender · correction

   Four Fender strings that used a spaced hyphen where the sentence needed a period or a colon now read that way instead: the Japan headstock-location note, the S-prefix country value, the T-prefix qualifier, and its disambiguation-prompt outcome. No claim, span, or source changed.

   Confirmed 2026-08-24 as a defect the copy gate's fatal-pattern list does not catch, because that list's em-dash rule targets the em-dash character, not this spaced-hyphen stand-in for it. Fixed by removing the pattern; the S-prefix value's rewrite also moved its verbatim quotation in this file's own 2026-08-09 entry, so that entry still quotes the string it describes.

   rules b4c2ea78 → 1799eb70

2. 1 September 2026 · Gibson · correction

   The plant-hint qualifier shared by two century formats used a spaced hyphen where the sentence needed a colon; both copies now read that way. No claim, span, or source changed.

   Same defect as the fender entry above: the copy gate's fatal-pattern list targets the em-dash character, not the spaced-hyphen stand-in, so this needed a manual pass rather than a lint catch.

   rules 7a7827ec → b76c7352

3. 28 August 2026 · PRS · refresh

   The headstock question on a short A serial now says what is in doubt: the instrument line, not the year. No serial changed the year it reads.

   A short A serial reads its year with confidence, but the same shape is also an SE serial numbered on a different chart. The page used to ask the question with the wording written for two competing years; it now says which thing is contested.

   rules 9bd63969 → 156ccc1d

4. 24 August 2026 · Taylor · refresh

   One word in Taylor's too-new reading is spelled differently: a contraction where the sentence used to spell it out. Nothing about which digits carry the year, which span the format covers, or which source backs it changed.

   This was the one Taylor sentence still spelling out the negation after the rest of the site's tables moved to the contracted form. Fixed so the phrase reads the same way everywhere it appears.

   rules fe94e7bc → eb108dc8

5. 24 August 2026 · Fender · refresh

   Fender's confidence notes and four miss reasons read differently across the table now. No serial changed the year it reads, and no span, bound or source moved.

   Every sentence a reader sees from this table was read against the site's copy register for the first time; the claims stand exactly where they stood, said more plainly.

   rules b5621c1c → b4c2ea78

6. 24 August 2026 · Gibson · refresh

   The wording under Gibson's confidence meter and its too-new miss reason reads differently now, plainer than before, and so does one of its next-steps checks. Nothing about which year a serial reads, which span a rule covers, or which source backs it changed.

   This table's reader-facing sentences went through the site's copy register for the first time. What changed is how each one is said, not what any of them claims.

   rules bb7bb988 → 7a7827ec

7. 24 August 2026 · Martin · refresh

   Martin's exclusion reason, one of its appraiser checks and its main-run confidence note read differently now: plainer, and free of the reused punctuation the rest of the site had already dropped. No year, span, bound or source moved.

   This is the first pass of Martin's reader-facing sentences against the site's copy register. The claims underneath are unchanged; the register just found plainer words for them.

   rules e8f134fb → 51545f78

8. 24 August 2026 · PRS · refresh

   PRS's confidence notes and miss reasons read differently across the table. The years, spans, bounds and sources behind them are exactly what they were.

   PRS's reader-facing sentences were read against the site's copy register for the first time here. The claims did not move; only the sentences carrying them got plainer.

   rules 138c05df → 9bd63969

9. 24 August 2026 · Squier · refresh

   Squier's miss reason, confidence note and one serial-location note read differently now, and one closing line matches the wording the other two Squier misses already use. No serial changed the year it reads, and no span, bound or source moved.

   Squier's reader-facing sentences were read against the site's copy register for the first time, including a check that its three miss reasons end the same way. The claims underneath are unchanged.

   rules 6fed8414 → d7a4bad1

10. 24 August 2026 · Fender · refresh

    One of the next steps we suggest for a Fender acoustic is spelled the American way. No serial changed the year it reads.

    The site's readers are in the United States and its copy is now held to US spelling throughout.

    rules 1d6d79bd → b5621c1c

11. 24 August 2026 · PRS · refresh

    The reason shown for an SE serial is spelled the American way in one word. No serial changed the year it reads.

    The readers here are in the United States, and US spelling is now the standard its copy is held to.

    rules 779de070 → 138c05df

12. 24 August 2026 · Squier · refresh

    Two words on the NC Bullet reading are spelled the American way: the reason shown, and one of the next steps we suggest. No serial changed the year it reads.

    This site writes for a United States readership, so its copy now holds to US spelling throughout.

    rules f3f7593c → 6fed8414

13. 24 August 2026 · Fender · expansion

    Three shapes that used to come back with no reading now name why they cannot be dated. A US serial with 18 through 29 after the letters, a KC serial with 13 through 29, and a CN serial with a 7, 8 or 9 each return the era they belong to and say that Fender's chart stops before them. No serial that had a year changed its year.

    Fender's American and Korean dating articles each stop at a last charted row (US17, KC12 and CN6), and a serial one row past the end is shaped exactly like the ones before it. Until now the site treated such a number as one it had never seen, which is the same answer it gives a typo. The number is recognized; what is missing is a published year for it, and the page now says that instead.

    rules c740c46b → 1d6d79bd

14. 24 August 2026 · Squier · expansion

    Two shapes that used to come back with no reading now name why they cannot be dated. A KC or KV serial with 13 through 29 after the letters, and a CN or VN serial with a 7, 8 or 9, each return the era they belong to and say that Fender's chart stops before them. No serial that had a year changed its year.

    Fender's Korean dating article stops at KC12 and CN6, and the Squier-specialist reference that records the KV and VN letters publishes no year rows of its own. A serial one row past the end is shaped exactly like the ones before it, and the site used to treat it as a number it had never seen. It is recognized; what is missing is a published year for it, and the page now says that.

    rules 5485aba8 → f3f7593c

15. 24 August 2026 · Fender · correction

    Three Fender readings changed after we read Fender's American dating article directly for the first time. A V serial of four digits, which the reissue run of 1982 to 1988 used, now reaches the American Vintage reissue answer instead of coming back with no reading at all; longer V serials already did. That answer now names the years Fender charts the line across, 1982 to 2017, and says the same article lists V numbers under Custom Shop instruments too, which is why the number names a line rather than a year. The S-prefix answer's note now states where Fender's chart actually puts each decal: S6 under 1976, S7 and S8 under both 1977 and 1978, and S9 under 1978 through 1981. The years a serial can return did not move. And the Mexico entry in the where-to-look table now says the back of the headstock or the neck plate, which is Fender's own answer, instead of describing a front-to-back move across the run.

    The article sits behind bot protection that returns nothing to an automated fetch, so until now the V span, the S-prefix placements and the Mexico serial position rested on a summary, a second Fender document, and a specialist chart respectively. Reading the article itself settled all three. The V span is charted rather than inferred, so the era can carry it; 2017 is where Fender's chart stops rather than where the numbering did, and the answer says so. The S-prefix placements were already recorded correctly in our source notes and only the reading of them was narrow. Fender publishes no serial position for its Mexican instruments at all, so the table now gives the general answer Fender does publish and stops there.

    rules 8f5d08cb → c740c46b

16. 23 August 2026 · Fender · correction

    A Fender serial opening with V, the American Vintage reissue line, used to come back reading 1982 or 2010. It now comes back naming the line, saying we cannot date it from the number, and telling you where the date actually is: pencilled or stamped on the heel of the neck. Fender's own dating article says the same thing, that taking the neck off is the only way to date one of these precisely, because the same V numbering ran across reissue runs decades apart with nothing on the outside to tell them apart. Those two years were never a pair Fender publishes. They were our shorthand for the openings of two long runs, and printed side by side they read as a choice between two years when the real answer is a window over thirty years wide. No other Fender serial is affected.

    Showing two years for a range that wide is the fake precision this site exists not to do. Our own rule is that an era we cannot read from the serial alone has to say so outright rather than dress the gap up as a short list, and the V prefix is that era: Fender charts it as one block and points past the serial for the year. The number still identifies the instrument as an American Vintage reissue, which is real information, and it now arrives with the neck-heel check that can actually date it instead of with two years that cannot. Typing a V serial without picking a brand still reaches this answer.

    rules f14274de → 8f5d08cb

17. 23 August 2026 · Fender · expansion

    Type a Fender acoustic or amplifier serial into the box without picking a brand and you are now offered Fender for it. You used to be offered nothing at all. Neither number sits on the year charts we read, and our Fender records have said so in writing all along: an acoustic serial, or an amplifier serial, comes back naming what the number is, why we will not read a year off it, and what to check instead. Until now that answer only appeared if you already knew to pick Fender by hand. No serial that read a year before reads differently.

    Auto proposes a brand from the shape of a number, and until now it only ever looked at the formats we can date. A serial we recognize and have deliberately declined therefore came back the way a mistyped number does: nothing matched, which is the least useful thing we can say about a number we know on sight. Auto now falls back to the shapes we have declined, and only ever as a last resort. If any brand's year chart claims the number at all, the declined shapes are not consulted, so a serial we can actually date is never crowded out by one we have already said we will not.

    engine 1.3 → 1.4

18. 23 August 2026 · PRS · expansion

    An SE serial typed without a brand picked now offers you PRS, and so does a PRS build number from below where the published charts open. Both used to offer nothing. On an SE the year lives in the leading letter, which PRS charts separately from the numbers we read, and our answer says so and links PRS's own chart; the early build numbers sit below where any chart we carry starts. Neither reads a year now and neither did before. What changed is that you no longer have to know it is a PRS to be told that.

    Auto proposes a brand from the shape of a number, and until now it only ever looked at the formats we can date. A serial we recognize and have deliberately declined therefore came back the way a mistyped number does: nothing matched, which is the least useful thing we can say about a number we know on sight. Auto now falls back to the shapes we have declined, and only ever as a last resort. If any brand's year chart claims the number at all, the declined shapes are not consulted, so a serial we can actually date is never crowded out by one we have already said we will not.

    engine 1.3 → 1.4

19. 23 August 2026 · Squier · expansion

    A Squier Bullet serial opening NC now offers you Squier without a brand picked first. It used to offer nothing. Those instruments were numbered without a year in the number, so we name the run and stop rather than guess at one, and that answer is now one step from the box instead of behind knowing the brand already. No serial that read a year before reads differently.

    Auto proposes a brand from the shape of a number, and until now it only ever looked at the formats we can date. A serial we recognize and have deliberately declined therefore came back the way a mistyped number does: nothing matched, which is the least useful thing we can say about a number we know on sight. Auto now falls back to the shapes we have declined, and only ever as a last resort. If any brand's year chart claims the number at all, the declined shapes are not consulted, so a serial we can actually date is never crowded out by one we have already said we will not.

    engine 1.3 → 1.4

20. 23 August 2026 · Martin · expansion

    A Martin number below where the published run opens now offers you Martin without a brand picked first. It used to offer nothing. Numbers that low sit before the sequence any chart we carry begins, so we say that and point at what dates the instrument instead. Nothing that read a year before reads differently.

    Auto proposes a brand from the shape of a number, and until now it only ever looked at the formats we can date. A serial we recognize and have deliberately declined therefore came back the way a mistyped number does: nothing matched, which is the least useful thing we can say about a number we know on sight. Auto now falls back to the shapes we have declined, and only ever as a last resort. If any brand's year chart claims the number at all, the declined shapes are not consulted, so a serial we can actually date is never crowded out by one we have already said we will not.

    engine 1.3 → 1.4

21. 23 August 2026 · Taylor · expansion

    A Taylor number from before 1993 now offers you Taylor without a brand picked first. It used to offer nothing. Taylor's published dating opens in 1993 and the numbers before it are not on it, so we name that and stop rather than reach for a year. Nothing that read a year before reads differently.

    Auto proposes a brand from the shape of a number, and until now it only ever looked at the formats we can date. A serial we recognize and have deliberately declined therefore came back the way a mistyped number does: nothing matched, which is the least useful thing we can say about a number we know on sight. Auto now falls back to the shapes we have declined, and only ever as a last resort. If any brand's year chart claims the number at all, the declined shapes are not consulted, so a serial we can actually date is never crowded out by one we have already said we will not.

    engine 1.3 → 1.4

22. 22 August 2026 · Fender · refresh

    Our record of what we can date closes the United States run at 2017 instead of leaving it open ended. Nothing you would see on a page changed. A United States serial from 2018 or later did not read as a year before this and does not now, every serial that did read a year still reads the same year, and the Fender coverage line still runs from 1976 to the present on the strength of the Mexico and Indonesia numbering.

    Fender's own dating article carries the US prefix only as far as US17, so 2017 is the last United States year we can point at a source for, and US18 upward is uncorroborated under our two-source rule. Our coverage record said 1976 onward anyway. That record sits behind the site rather than on it, so no reader was told anything untrue, but it is what our own check reads when it asks whether a coverage claim is backed by the formats that serve it, and a record that overstates what we carry is how an overstatement reaches a page later. The rule itself is untouched: we did not widen the US prefix to cover years no source charts.

    rules dc08a14b → f14274de

23. 22 August 2026 · Fender · correction

    Answering the headstock question on a Fender now gives you the whole run the answer lands on rather than one year out of it. Tell us your six-character S serial carries no country marking and the answer used to read 1977; it reads 1976 to 1981 now, which is the run Fender's chart gives that shape. Say 'Made in Japan' instead and it reads 1994 to 1995 rather than 1994, and a 'Crafted in Japan' S serial reads 2006 to 2008 rather than 2006. The price context under the answer follows: it searches on the brand now, where it used to search on that one year. Separately, a Fender number newer than our chart now names the last year our records are checked through, and the list of what we checked leads with the Fender chart and the years it spans. No year, run or source was re-sourced or widened. Every span above was already in our tables.

    The run was in our records the whole time and was already spelled out under the answer, in the line saying why the reading is probable rather than certain, while the largest number on the page named a single year out of it. On the S serials that gap is wide: Fender's own chart lists 'S9 + 5 digits' under 1979, 1980 and 1981, because the decals were used up long after the calendar turned, so the year we printed could sit several years from the instrument in your hands. A number that reads as one certain year, with the qualification sitting underneath it, is a hedge dressed as an answer, and the reader who reads only the answer gets a precision we do not have. The chart bound was the same shape of problem one level down. Our Fender coverage line reads '1976–present', the miss page was reading a last year out of that wording, and the word present is not a year, so the sentence lost its year and the list lost its chart row. Both bounds now travel with the reading itself instead of being rebuilt from prose.

    engine 1.0 → 1.1

24. 22 August 2026 · Taylor · refresh

    A Taylor number newer than our chart now names the last year our records are checked through, and the list of what we checked leads with the Taylor chart and the years it spans. That answer used to say only that the chart ends at its last row, with no year in the sentence and no chart row in the list. No serial changed the year it reads, and nothing changed about which numbers we can date.

    That sentence is the whole answer on this page: it tells the owner of a nearly new Taylor that the number is fine and our records have not reached it yet. Without a year it does not say when they will. The year was there to be printed, in the coverage our own tables declare, but the page was reading it out of the wording of the coverage line rather than out of the tables, and the Taylor coverage line reads '1993–present'. The word present is not a year, so there was no year to pull out of it, and the answer went short in two places at once: the sentence lost its year and the list lost its chart row. The reading now carries the chart's first and last year itself, so the sentence names a year on every brand that can give this answer.

    engine 1.0 → 1.1

25. 22 August 2026 · Gibson · refresh

    A Gibson number newer than our chart now names the last year our records are checked through, and the list of what we checked leads with the Gibson chart and the years it spans. That answer used to say only that the chart ends at its last row, with no year in the sentence and no chart row in the list. No serial changed the year it reads, and nothing changed about which numbers we can date.

    That sentence is the whole answer on this page: it tells the owner of a nearly new Gibson that the number is fine and our records have not reached it yet. Without a year it does not say when they will. The year was there to be printed, in the coverage our own tables declare, but the page was reading it out of the wording of the coverage line rather than out of the tables, and the Gibson coverage line reads '1977–present'. The word present is not a year, so there was no year to pull out of it, and the answer went short in two places at once: the sentence lost its year and the list lost its chart row. The reading now carries the chart's first and last year itself, so the sentence names a year on every brand that can give this answer.

    engine 1.0 → 1.1

26. 22 August 2026 · PRS · refresh

    A PRS number newer than our chart now names the last year our records are checked through, and the list of what we checked leads with the PRS chart and the years it spans. That answer used to say only that the chart ends at its last row, with no year in the sentence and no chart row in the list. No serial changed the year it reads, and nothing changed about which numbers we can date.

    That sentence is the whole answer on this page: it tells the owner of a nearly new PRS that the number is fine and our records have not reached it yet. Without a year it does not say when they will. The year was there to be printed, in the coverage our own tables declare, but the page was reading it out of the wording of the coverage line rather than out of the tables, and the PRS coverage line reads '1985–present'. The word present is not a year, so there was no year to pull out of it, and the answer went short in two places at once: the sentence lost its year and the list lost its chart row. The reading now carries the chart's first and last year itself, so the sentence names a year on every brand that can give this answer.

    engine 1.0 → 1.1

27. 22 August 2026 · Fender · refresh

    Five Fender lines of explanation are worded differently. The reasons shown for an acoustic and for an amplifier, the candidate note on an S-prefix serial, and the two Mexico notes say what they said before in plainer words. No serial changed the year it reads, no confidence level moved, and no source changed.

    All five narrated our own candour rather than stating the record, which the site's copy register bans, and every one of them renders: the two reasons are the lede on a miss page, the candidate note sits on the ambiguous card, and the Mexico notes sit under the confidence meter. The claims are untouched. An acoustic still yields no year from its serial, an amplifier is still dated from the tube chart, an S-prefix serial still runs as late as 1981, and the Mexico rules still read probable because of the production lag.

    rules da1e32da → dc08a14b

28. 22 August 2026 · PRS · refresh

    The reason shown for an SE-series serial is worded differently. No serial changed the year it reads.

    That reason is the lede on the miss page an SE owner sees, and it narrated our own candour rather than saying what happens, which the site's copy register bans. It now states the behavior directly: the engine recognizes the SE prefix and sends the reader to the PRS chart that carries the letter-to-year scheme. The scope of the exclusion and the source behind it are unchanged.

    rules f15ece5d → 779de070

29. 22 August 2026 · Squier · refresh

    The reason shown for an NC-prefix Squier Bullet serial is worded differently. No serial changed the year it reads.

    It is the lede on the miss page for every NC Bullet serial, and it narrated our own candour rather than stating the record, which the site's copy register bans. What it claims is unchanged: Fender publishes no year chart for that run and marks the dating unclear, so the number is recognized and deliberately not dated.

    rules d25961d9 → 5485aba8

30. 22 August 2026 · Squier · correction

    A Korean Squier serial beginning CN7, CN8, CN9, VN7, VN8 or VN9 no longer comes back as 1997, 1998 or 1999. Those three years are not charted against that prefix by anything we can point to, so the number is not dated here at all. Separately, the coverage line for Squier now closes at 2012 instead of reading as though we can date a current one. Nothing else about Squier changed: CN3 through CN6 still read 1993 through 1996, and the KC and KV run still reads 1997 through 2012.

    The single digit after CN or VN gives the year, and we were running that arithmetic three years past the last row of the chart it came from. Fender's Korean article carries no CN row after CN6 and introduces the KC prefix at 1997 instead; the Squier reference that corroborates the digit rule publishes no year rows of its own. So 1997, 1998 and 1999 were our arithmetic rather than anybody's record, and they contradicted our own KC and KV rule, which already covers those years from a different prefix. The coverage line had the same shape of problem one level up. It was left open-ended while every Squier format we carry stops in 2012 or earlier, which told a reader we could date a modern Indonesian or Chinese Squier when we carry no format for one.

    rules 62a65d6d → d25961d9

31. 22 August 2026 · Fender · correction

    The coverage line for Japan-made Fender instruments now reads 1982 to 2010 rather than 1982 onward. No serial changed the year it reads.

    The newest Japanese format we carry is the reused T prefix, and its latest run ends in 2010. Nothing in our tables reaches past that. Saying 'onward' told the owner of a 2015 Made in Japan instrument that we could date theirs, and then handed them a number we did not recognize, which is the answer we give a typo. The coverage line exists to say where our records stop, so it now stops where they do.

    rules fe682b1d → da1e32da

32. 22 August 2026 · Taylor · refresh

    A short Taylor number, of the kind used before our charts open in 1993, now comes back as a Taylor from before our records start, with the reason and the checks worth making on the instrument. It used to come back the same way a mistyped number does, with nothing said.

    Taylor's own decoding page opens at 1993, and the company was building guitars for years before that. Every other brand here says so where its charts begin: Gibson, Fender, Martin, PRS and Squier all name the era below their coverage and point the reader at what does date the instrument. Taylor named nothing, so the owner of an early Taylor got the answer we give a number we cannot read at all. No year changed for any serial our charts do cover.

    rules b3b1dd2c → fe94e7bc

33. 22 August 2026 · PRS · correction

    A PRS acoustic serial with five or six digits after the A no longer comes back as a year on its own. It now comes back as one candidate year with a question attached: does the headstock say SE? Answer no and the year stands, and stands as a certain one. Answer yes and the answer becomes the SE page instead, which sends you to PRS's own SE letter chart, because an SE serial is numbered on a different chart entirely and the acoustic year was never that instrument's. Longer A serials, with seven digits, are unambiguous and still read as a certain year straight away. No serial changed which year it reads.

    We had already admitted in writing that this shape could be an SE and that our year would not apply to one, and then printed the year anyway, with the caveat sitting underneath it. An owner reading their SE serial had to notice the caveat, understand it applied to them, and disregard the large number above it. An answer that depends on a footnote to be true is a hedge. The SE page was in our tables the whole time and no serial of this shape could ever reach it, because the year rule always answered first. Asking one question puts both readings on the page as equals and lets the owner say which instrument is in their hands, which is the only thing that actually separates them.

    rules 30bb9b0e → f15ece5d

34. 19 August 2026 · PRS · correction

    A PRS acoustic serial with five or six digits after the A now comes back as a probable year rather than a certain one, and says why: an SE serial can read the same way, and PRS dates those from a separate letter chart. If the headstock says SE, the year we show does not apply. Longer A serials, with seven digits, are unambiguous and still read as a certain year. No serial changed the year it reads: only how sure we say we are about the shorter shape.

    We were answering a certain acoustic year for a number that an SE owner could type in and get back. The year would have been wrong for them, and nothing on the page would have hinted at it. Splitting the rule by length lets the unambiguous shape keep its certainty while the ambiguous one carries the doubt where the reader can see it. Making every A serial a miss instead would have taken a real, dateable acoustic reading away from the owners it belongs to.

    rules 3364bff3 → 30bb9b0e

35. 19 August 2026 · Squier · correction

    Korean Squier serials beginning CN0, CN1, CN2, VN0, VN1 or VN2 no longer return a year. They used to read as 1990, 1991 and 1992. Fender's own Korean dating article says its digital records begin in mid-1993 and that CN numbers before then are undocumented, so those three years were ours, not the source's. A serial of that shape now comes back as one we cannot read from the number, which is what the source supports. Serials from CN3 through CN9 and VN3 through VN9 are unchanged, and the era is now named for the years it actually covers, 1993 to 1999.

    The era was already labeled '1993 onward' while the rule answered three years earlier than that: the label and the rule disagreed, and the rule was the one making the claim. Fixing the label instead would have published the three unwarranted years under our own name. Fender's Fender-branded table already left the same digits unread; this brings the Squier table into line with the source both tables cite.

    rules 051250eb → 62a65d6d

36. 16 August 2026 · Gibson · correction

    A correction to the sourcing notes behind our Gibson rules. Nothing on any page changed and no serial decodes differently. One note claimed that Gibson's own serial-number page documents the 2014 to mid-2019 nine-digit run, and that every rule resting on the Gibson App reference also rests on Gibson's own page. Neither is true. Gibson's page describes the day-of-year coding, the 2005 batch form, the 1994 centennial and the factory bands, and stops there. The rule we added for the 2014 to mid-2019 run is the first Gibson rule of ours that stands on two independent references with no manufacturer document behind it, which is what our sourcing standard asks for when no manufacturer document exists. The note now says so.

    We publish nothing from these notes, but they are the record anyone auditing us would read, and this one pointed at corroboration on Gibson's own site that is not there. Someone checking would have gone looking for it, found nothing, and had every reason to wonder what else we had overstated. A rule that stands on two independent references is worth saying plainly rather than dressing in an anchor it does not have.

    rules 0d9b53f2 → bb7bb988

37. 16 August 2026 · Gibson · expansion

    A Gibson serial from the 2014 to mid-2019 run now comes back with a year. Between those dates Gibson used a nine-digit number with no day of the year in it: the first two digits are the model year and the seven behind them count production. Nothing in our tables read that shape, so five model years of Gibson production came back as nothing matched. They now read a year, marked probable rather than certain, with a line under the answer explaining that the year is the model year Gibson stamped and that a model year opens in the autumn before the year it names, so an instrument reading 2015 may have been finished in late 2014. Gibson closed the run in the middle of 2019 and went back to the day-of-year coding, so a 2019 instrument may carry either shape. No serial that already had a year gets a different one: the two shapes cannot overlap, because a day-of-year number's second digit is 0 to 3 and this one's is 4 to 9.

    Our Gibson coverage says 1977 onward, and for five of those years it was not true. The run is documented by two independent references and we had already recorded both of them in our own notes, so the change was to read the number rather than to keep declining it. What we would not do is call the year certain: the number states a model year, not a build date, and the sources are clear that those are not the same thing. So the answer is a single year at probable confidence with the caveat spelled out, rather than a confident year we cannot stand behind or a two-year range no source actually supports.

    rules 8f2aa871 → 0d9b53f2

38. 16 August 2026 · Fender · refresh

    One paragraph rewritten. The explanation under the confidence meter on an N-prefix Fender reading tells the same story (decals printed long before the guitars they went on, a batch of 1999 decals used up on 1990 instruments, and an N9 still reading 1999 here) in our own sentences rather than in Fender's. The year, the span and the confidence level are untouched, and no serial decodes differently.

    Our rules are written from published sources but never in their words, and that paragraph had been carrying a run of Fender's own sentence into a page we publish. We keep the manufacturer's exact wording in the notes behind the rule, where it is the evidence that the rule is right; what we print is ours. The wording was inherited from an older version of the note and survived last night's rewrite, which is exactly the kind of thing a second read is for.

    rules 8a5e662c → fe682b1d

39. 16 August 2026 · Gibson · refresh

    The paragraph printed under the confidence meter on a Gibson reading is rewritten in plain English. It now says how the year is spelled out of the number (the first digit and the fifth, read together as a pair), which decade that lands in, and what makes the reading a certain one. Every year, every fact and every level of confidence is exactly what it was, and no serial decodes differently.

    That paragraph is written for you, not for us, and it had stopped reading that way. It named our own build process, it named the way our Gibson rules are split in two behind the scenes to satisfy a pattern-matching limitation, and it spent much of its length on numbers you had not typed and would never be shown an answer for. None of that helps anyone weigh the year in front of them. The engineering reasoning has moved into our authoring notes, where it is kept in full and shown to nobody, and what is left on the page answers the question you actually asked.

    rules 1d1d3cad → 8f2aa871

40. 16 August 2026 · Fender · refresh

    The paragraph printed under the confidence meter is rewritten on every Fender reading that had been carrying working notes instead of an explanation. The Korean and Indonesian readings lose a block of internal bookkeeping about where our chart stops and why; the N-prefix reading keeps Fender's own recorded 1999-decal-in-1990 exception but drops the note-to-self around it; the S-prefix reading keeps the headstock-wording test and the 1976 to 1981 span but loses a paragraph about how our own records are arranged. The decade prefixes (E, N, Z, MN, MZ, MX, US, CN) drop a phrase that described our machinery rather than your guitar. No serial decodes differently.

    Everything above renders on the answer page, under the meter that tells you how sure we are. Some of it had been written as though only we would read it: references to our issue tracker, to the internal names of our own rules, and to a decision about where one of our charts ends that matters to whoever maintains it and to nobody else. The reasoning is not lost (it now sits with the sources it belongs to, in the notes behind each rule), and every sentence still on the page is there because it tells you what the year rests on.

    rules c903b8b6 → 8a5e662c

41. 16 August 2026 · Squier · refresh

    The paragraph printed under the confidence meter on a Korean Squier reading is rewritten in plain English. A KC or KV serial still reads the two digits after the letters as the year, still covers 1997 through 2012 and no further in either direction, and still comes back as a probable year rather than a certain one, but the explanation is now written for the person holding the guitar rather than as a record of the day we changed it. The CN and VN reading drops a phrase describing our own machinery. No serial decodes differently.

    That paragraph had turned into a change log. It carried the date of an earlier correction, the reference number we filed it under, the name one of our Fender rules goes by internally, and quoted wording from the sources instead of saying the thing in our own words. All of that already lives in the notes behind the rule, alongside the sources themselves, which is where anyone auditing us would look for it. What is on the page now is the shape of the number, the years it can cover, and why the answer is probable rather than certain.

    rules ea590a6c → 051250eb

42. 16 August 2026 · PRS · refresh

    Two small wording changes on PRS. The paragraph under the confidence meter on an acoustic or a 2008-onward set-neck reading says a leading pair of digits is read as a 2000s year, instead of describing the internal setting that does it. And the answer for a PRS too early for the published chart now says such an instrument is identified by its construction and its documented history, rather than using a word that also names one of our own data fields. No serial decodes differently.

    Both lines are shown to readers. One described a piece of our own machinery by its internal name, which tells you nothing about your guitar. The other used a word that reads perfectly well to a collector but that we use internally for our source records, so it was worth saying the plainer thing in a sentence whose whole job is to tell somebody what to do next.

    rules b1b82b69 → 3364bff3

43. 16 August 2026 · Taylor · refresh

    The paragraph under the confidence meter on the two modern Taylor readings is rewritten in plain English. An eleven-digit serial from the 2000s now simply says the first four digits state the year outright rather than coding it; a ten-digit serial from 2009 onward says which two digits carry the year and in which order they are read. The years, the spans and the confidence levels are unchanged, and no serial decodes differently.

    Both sentences had been written in the vocabulary of the thing that reads the number rather than the vocabulary of the person reading the answer: one described an internal setting, the other talked about digits being captured. Neither told you anything you could act on. The replacements say the same thing in words that mean something with the guitar in your hands.

    rules 0318ea69 → b3b1dd2c

44. 16 August 2026 · Gibson · correction

    A six-digit Gibson number still comes back undated, with the same explanation and the same three checks, but it is no longer filed under the years 1961 to 1975. The answer now calls it what it is: a six-digit Gibson serial from before 1977. Two other lines that named the same fifteen years (the note about where the number is stamped, and the note attached to the late-seventies readings) now say pre-1977 as well. The page and the guide written about that era keep their names and their addresses, and no serial gets a different year.

    The old wording put a year span on numbers it could not be sure of. Gibson opened the eight-digit coding in 1977, and the charts we hold run the six-digit numbers to 1975, so a guitar built in 1976 carries six digits that no chart we hold covers, and that guitar was being handed an answer headed with a span that ended the year before it was built. Naming the shape of the number instead is true of every number that lands there, 1976 included. The paragraph explaining why these numbers cannot be dated is our published wording and is unchanged.

    rules eda43998 → 1d1d3cad

45. 16 August 2026 · Gibson · correction

    A note in our records, not a change to any answer. Gibson serials carry the day of the year in digits two to four, and we accept 366 there so that December 31st of a leap year can be read. Our notes now say plainly where that comes from: Gibson's own page puts no limit on the field, and the reference that does print one prints 365 while its own lookup tool answers a 366 anyway. No serial reads differently.

    Anyone checking our Gibson rules against the pages behind them would have read 365 in print, seen us accept 366, and had nothing on file explaining the difference. What settled it was the tool rather than the prose: the serial 83660001, whose day digits are 366, comes back from that reference's own lookup as December 31 1980 (a leap year, and the same year we return). Both pages were read again on 16 August 2026 to confirm what each one does and does not say.

    rules a359efdd → eda43998

46. 16 August 2026 · Gibson · correction

    The note about Gibson's factories on any serial from 2000 onward no longer says that semi-hollow bodies came from Memphis until 2019. It now names the two places our sources name: acoustics from Bozeman since 1989, electrics from Nashville. Every year and every ranking-number reading is unchanged.

    Nothing behind that chart said it. Gibson's own serial page names Gibson Memphis once, as one of the three divisions whose numbers the page explains, and says nothing there about semi-hollow instruments or about 2019. One specialist reference we cite says Gibson electrics are built in Nashville or Memphis, which is a single source and is not the same claim. A sentence with a year in it that no reference we hold puts a year on is a sentence we should not be printing next to an answer.

    rules d532c8db → a359efdd

47. 16 August 2026 · Fender · correction

    Our Korean KC chart now stops where Fender's own does. A serial from KC97 to KC12 still reads the two digits after the letters as the year, from 1997 through 2012. A number outside that run (KC13 and later, or the KC93 to KC96 pairs) matches nothing we hold, and the answer says so rather than naming a year or telling you the number is newer than our records.

    Earlier today we started reading the year out of a KC serial, which was the fix that mattered, but we read every possible pair of digits and Fender only publishes rows for sixteen of them, one for each year from 1997 to 2012. Anything after that was our arithmetic rather than anybody's record. Anything before it was worse: the prefix did not exist until 1997, so a KC93 number was being told it was newer than our records when the shape is one Fender never issued at all. This is the same limit our United States chart already keeps at US17. Where the published rows end, we end, and the date our sources were last checked never extends them.

    rules 26b9d967 → c903b8b6

48. 16 August 2026 · Squier · correction

    Three changes to Korean Squier serials beginning KC or KV. The number is now read at the length both our sources give it (the two letters, two digits for the year, then six more), so a KC or KV number with only five digits behind the year is no longer read as a year. The run opens in 1997 rather than 1993, so KC93 through KC96 no longer come back as 1993 through 1996. And it closes at KC12: a later pair matches nothing we hold, where it used to come back as newer than the records we have checked.

    All three came out of reading Fender's Korean article in full again on 16 August 2026, alongside the Squier reference we cite with it. Fender introduces the KC prefix in 1997 and charts one row a year from KC97 to KC12, so the four years we were answering below that opening had no source behind them, and the pairs above it were arithmetic rather than record. On the length, both sources say eight digits follow the letters, which meant the form they document did not read here while a form neither of them describes did. Our Fender charts moved to the same bounds on the same day, so a Korean number that could belong to either brand now gets the same year whichever way it is read.

    rules 11f3c04e → ea590a6c

49. 16 August 2026 · Fender · correction

    Korean-made Fender instruments are now dated from the digits in the number rather than from one four-year window. A serial beginning KC reads the two digits after the letters as the year (KC97 is 1997, KC05 is 2005), and a serial beginning CN reads the single digit after the letters the same way, so CN5 is 1995. Both come back as a probable year rather than a certain one. Two numbers stop getting an answer here. A KV serial no longer matches the Fender charts at all: the only reference that records that prefix covers Squier instruments, so a KV number is answered by our Squier charts instead. And a CN0, CN1 or CN2 serial is left unread rather than dated.

    The window was contradicted by both references behind it. Fender's own Korean article introduces the KC prefix in 1997 and says the first two digits after the letters identify the year of manufacture, charting a row for every year from KC97 to KC12; the Squier-specialist reference we cite alongside it says the same thing in its own words. So a KC97 number, which cannot be older than 1997, was being answered with 1993 to 1996, and our own Squier charts, reading the same digits, answered 1997. A wrong year is worse than a vague one, and two of our own charts disagreeing about one number is worse than either. The KV prefix went the other way: Fender's article has no KV row anywhere, and the only reference that charts the letters is a Squier one, so there was nothing behind a Fender-branded KV reading to keep. The CN digits 0, 1 and 2 are declined for the reason Fender gives itself: its Korean digital records begin in the middle of 1993, and it says the numbers before that are undocumented. The article was re-read in full on 16 August 2026 before any of this moved.

    rules 15094b09 → 26b9d967

50. 16 August 2026 · Fender · correction

    Three corrections to the Fender tables. A T serial from Japan now comes back with three possible runs instead of two: Fender's own chart records a Made in Japan run from 1994 to 1995 alongside the two that open in 2007, and we had missed it. Answering that your headstock says Crafted in Japan still settles the reading; answering Made in Japan now leaves the two Made in Japan runs standing, because nothing in the number separates them. Second, the Korean prefixes no longer say that Fender's chart names a Vester factory: it does not, and it names no factory for anything but KC, which it puts at Cort. The plants behind KV and CN come from a Squier-specialist reference, and we now say so. Third, the Mexican serial position no longer claims the number is always on the front of the headstock.

    A Made in Japan T serial from the mid-nineties was being answered with a span from 2007, which is a wrong year rather than a vague one, so the missing run had to go into the table rather than into a footnote. The Vester factory was our error: Vester is a brand the Saehan plant built, not a plant Fender names, and our own Squier table had it right while the Fender one did not. And on the Mexican position, Fender's own article names no face of the headstock at all, while the reference we cite alongside it puts the earlier prefixes on the front and the later ones on the back, so the flat statement we were making was one no source supported. The references behind these charts were re-read on 16 August 2026 as part of the same pass, and the date stamped on each of them moved with the reading.

    rules 1fe5456e → 15094b09

51. 16 August 2026 · Gibson · correction

    The advice we hand back on a 1961 to 1975 Gibson has changed, and so has one line about the factory. The factory order number is no longer on the list of checks: every reference we cite ends its letter codes in 1961, the first year of that fifteen-year span, so it cannot date the six-digit numbers that answer is written for. The three checks that remain are the stamp under the number, the potentiometer codes and the headstock. The stamp's split is now stated as 1963 to 1969 without it and 1970 to 1975 with it, rather than 1961 to 1969, because the chart behind it puts the earlier numbers at five digits rather than six. And on the modern numbers, the ranking-number bands no longer both end in 1984: the low band ended with the Kalamazoo factory that year, while the high band went on naming Nashville until 1989.

    A page whose whole job is to say what to check instead of the serial was sending readers to a check that stops at the first year of the era. That is worse than saying nothing. The other two are the same kind of error in miniature: a date range stated wider than the chart behind it, and a sentence that dropped the second half of what Gibson's own page says about its factory numbers. One source citation also changed class: the Gibson-branded lookup app is built and run by another company, so it is now counted as a specialist reference rather than as manufacturer documentation. The references behind these charts were re-read on 16 August 2026 as part of the same pass, and the date stamped on each of them moved with the reading.

    rules c9311090 → d532c8db

52. 16 August 2026 · PRS · correction

    The PRS charts no longer name a factory. The set-neck numbers from 2008 onward were recorded against Stevensville, Maryland, and the note on SE instruments described the numbers this engine reads as the US-made Core line. Both have been taken out. Every year these charts return is unchanged.

    No PRS source we cite says either thing. PRS's year-identification page, which is the spine of all of this, names no plant, city, state or country for any line it dates (it charts the SE instruments under Korea and Indonesia headings and stops there), and neither do the three dealer references beside it. Naming a place on one chart also implied the serial number records where the instrument was built, which is a second claim none of them makes.

    rules 9417fbd3 → b1b82b69

53. 16 August 2026 · Squier · correction

    The authenticity caution on the Japanese JV and SQ numbers has been reworded. It used to call those prefixes prevalently forged. It now says what we can actually stand behind: these are the checks that community authentication threads make on one (reproduction decals, re-stamped neck plates, Squier-to-Fender logo swaps) and that a serial number cannot prove an instrument is genuine. The two forum threads behind it are now recorded as owner reports rather than as specialist references. Separately, the Korean note no longer says Fender's article documents a KV prefix; it documents KC, and KV comes from the Squier reference cited alongside it.

    How often JV and SQ instruments are faked is a claim about the world, and our only two sources for it are forum threads that no longer serve their contents to anything but a browser, so we cannot check them and would not lean a frequency claim on them if we could. What those threads do establish is that the checks get made, which is the useful half for anyone holding one of these guitars. The caution still sits on both charts and still carries the same weight in the answer. The references behind these charts were re-read on 16 August 2026 as part of the same pass, and the date stamped on each of them moved with the reading.

    rules ed680e85 → 11f3c04e

54. 15 August 2026 · Fender · refresh

    The further-reading links on our Fender pages now point at articles we are actually publishing. The seven questions that turn on what your headstock says (the six reused Japan letters, and the S prefix that a United States and a Japanese instrument can share) all now point at our article on Made in Japan versus Crafted in Japan. The pre-1976 exclusion points at our Fender serial history article. The links from our acoustic and amplifier notes, and from the two too-new readings, have been taken away entirely.

    No serial reads differently and no reading has changed its wording. Behind each of those links sat the name of an article, and several of those articles were never going to be written: we had named more of them than we intend to publish, and a link to a page that does not exist is worse than no link at all. Where a real article covers the question, the link now names that article. Where none does, we say what we know and stop, rather than sending you somewhere empty: our acoustic and amplifier notes already tell you what to look at instead, and a reading that is simply newer than our records already says so and gives you Fender Customer Service.

    rules 9e1f0f12 → 1fe5456e

55. 15 August 2026 · Gibson · refresh

    The too-new reading on Gibson's eight-digit numbers no longer carries a further-reading link. Everything it tells you is unchanged: the year the number points at is later than the records we have checked, we won't guess at it, and it still gives you Gibson Customer Service and the date of our next refresh.

    No serial reads differently. That link named an article we are not publishing, so it would have led nowhere. The Gibson 1961 to 1975 exclusion keeps its link, because that one names an article we are publishing.

    rules 64cb5e49 → c9311090

56. 15 August 2026 · Martin · refresh

    Three further-reading links have been taken off Martin readings: the one on numbers below where the run opens, the one on the Sigma-Martin label question, and the one on a number newer than the chart we carry. Nothing else about those three readings has changed.

    No serial reads differently. Each link named an article we are not publishing, and a link that leads nowhere is worse than none. All three readings already carry the explanation and the checks to run in their own words (what the number is likely to be, what to look for on the instrument, and who to ask), and none of that depended on the link.

    rules 324c36fb → e8f134fb

57. 15 August 2026 · PRS · refresh

    The further-reading links have been taken off every PRS reading that carried one: the pre-1985 and SE exclusions, the ten single-digit decade questions, and the two too-new readings. The questions themselves, the answers, the reasons and the checks to run are all unchanged.

    No serial reads differently. Those links all named the same two or three articles we are not publishing. The decade questions are the clearest case: each one already tells you exactly what to look at (the sequence of digits after the leading one), and asking you to read an article first would have added nothing. The SE and pre-1985 notes already point at PRS's own year-identification page, which is the better destination anyway.

    rules a28c9d86 → 9417fbd3

58. 15 August 2026 · Squier · refresh

    Two further-reading links have been taken off Squier readings: the one on the NC-prefix Bullet instruments Fender itself marks as unclear, and the one on a Korean KC or KV number newer than our records. Both readings say exactly what they said before.

    No serial reads differently. Both links named an article we are not publishing. The NC reading already explains that Fender publishes no year chart for that run and that the number is recognized but deliberately not dated, and the too-new reading already gives you Fender Customer Service and our refresh date.

    rules 34135552 → ed680e85

59. 15 August 2026 · Taylor · refresh

    The too-new reading on Taylor's ten-digit numbers no longer carries a further-reading link. What it tells you is unchanged: the year sitting in the second and seventh digits is later than the records we have checked, we won't guess at it, and Taylor's support team can place the instrument sooner than our next refresh can.

    No serial reads differently. The link named an article we are not publishing, so it would have led nowhere.

    rules 3823a649 → 0318ea69

60. 15 August 2026 · Gibson · refresh

    We have written down a Gibson numbering run our charts do not cover: from 2014 until the middle of 2019, many Gibson serials put the year in the first two digits and a plain production count behind it, with no day of the year in the number at all. Nothing decodes differently. A serial in that shape still comes back as one nothing in our data matches, and it now says so with the source for the gap recorded alongside it.

    Our Gibson pages explain why a number from those years can fail to match anything, and that explanation had nothing behind it in our own records. Two sources describe the run (Gibson's own lookup reference and one of the independent guides we already cite), so we have written what they say into the source note for the page we read it on. We would rather say plainly which years our charts miss than leave a reader guessing whether the fault is their number or ours.

    rules ab5d84fb → 64cb5e49

61. 15 August 2026 · Fender · refresh

    The two answers on the S-prefix question are short again. Each one now tells you the reading it settles on, and the reasoning behind it has moved into the note we keep against that rule.

    No serial reads differently and nothing we say has changed its meaning. The answers to that question are meant to be read at a glance, in the width of the button you tap, and earlier today we let two of them grow into paragraphs while explaining the fixes we had just made. The explanations were worth keeping, so they now sit in the rule note where the long-form reasoning for that rule already lives.

    rules e3efbc66 → 9e1f0f12

62. 15 August 2026 · Fender · correction

    Three fixes to what we say about US-made Fenders. We no longer name a factory town on any of them. The S-prefix reading now runs from 1976 to 1981 rather than closing at 1979. And when you tell us your headstock says 'Crafted in Japan', we no longer tell you an S prefix was never used in that era: it was, and we carry the reading for it.

    The factory town was the plainest of the three. Every US serial we dated said it was built in Corona, California, and neither of the Fender documents we rely on names a town anywhere (not the support article, not Fender's own dating handout, which we read end to end). Fender also did not move to Corona until the mid-1980s, so a 1976 or 1980 instrument was built somewhere else entirely, and a serial from the E run straddles the move. We could not source the factory history to the standard we hold ourselves to, so we now say United States and stop there. On the S prefix: Fender's own chart lists an S9 number against 1979, 1980 and 1981 alike, while we were closing that reading at 1979, so we were quietly ruling out two years Fender itself allows, and the reading now covers 1976 to 1981. On the Crafted in Japan answer: our own Japan table documents an S prefix used from 2006 to 2008, so the wording contradicted a reading sitting one row below it. The answer already sent you to the right place; only the sentence was wrong, and it now says what actually happens. Two era headings were adjusted to match the years the readings behind them can actually give you, and the years column on those tables no longer says 'present' for a reading that stops at the end of its decade.

    rules 583c9cb1 → e3efbc66

63. 15 August 2026 · Fender · refresh

    Our note on the 1990s N-prefix numbers now records a rare exception Fender documents: a batch of decals reading 1999 was fitted to instruments built in 1990, so a few 1990 guitars carry a 1999 number. The normal drift is still a year or two, and an N9 serial still reads 1999.

    No serial reads differently. Our note already said these numbers can sit a year or two off the calendar, and that is still the usual case. Fender's own dating document also records one batch that went much further, and we would rather have both facts written down in the same place than have a page mention the rare case while the note behind it appears to contradict it. We have also written the exact wording of the Fender statements our Fender pages rely on into the source note, so every claim on those pages can be traced without anyone having to re-read the original document.

    rules 26e339f8 → 583c9cb1

64. 15 August 2026 · Fender · refresh

    The Fender document we added yesterday for the 2009-2010 '10' prefix now records who publishes the site it came from.

    No serial reads differently. A reviewer asked a fair question about that source: it sits on fenderacademy.com rather than fender.com, so is it really Fender's own material? We checked, and the site's footer names Fender Musical Instruments Corporation as its owner. We have written that check into the source note, with the date we made it, so nobody has to repeat it.

    rules 25188582 → 26e339f8

65. 15 August 2026 · Fender · refresh

    The short-lived '10' prefix, used on US-made instruments from late 2009 into March 2010, now cites a second Fender-published document alongside the support article it already cited.

    No serial reads differently. Our page about US serial numbers explains what that prefix means, including the detail that the '10' was printed on the instrument decal but was never entered into Fender's own database, and that the country of origin was on the decal rather than inside the number. That detail was not written down in the sources we list, so we have added the Fender document it comes from and pointed the rule at it. We would rather cite one more source than leave a claim on the page with nothing behind it.

    rules f94d54e9 → 25188582

66. 14 August 2026 · Gibson · refresh

    A Gibson serial whose 1st and 5th digits point to a year newer than the records we have checked now says so plainly, instead of coming back as a number we do not recognize. The note explaining the 2000s and 2010s format has been corrected as well: it still described a fixed end year that no longer exists.

    Neither part of this changes the year any serial reads. Gibson was already declining these numbers rather than guessing at them; what changes is that we now tell apart a number we cannot place at all from one that is simply newer than our records, and point you somewhere useful for the second kind.

    rules 6fe14d02 → ab5d84fb

67. 14 August 2026 · Fender · refresh

    A Mexico or Indonesia serial whose year digits point past the newest year our sources verify now says plainly that it is newer than our records, instead of coming back as a number we do not recognize.

    These serials were already being declined rather than given a year, so no reading changes. What changes is what we say about them. A number we cannot place at all and a number that is simply newer than the records we have checked are two different situations, and separating them lets us tell you which one you are looking at. Every other brand that can run past its records already answered this way.

    rules 1611ebb1 → f94d54e9

68. 14 August 2026 · Gibson · refresh

    Gibson coverage no longer stops at a hand-written end year. No serial decodes differently: this only changes how a too-new serial is declined, not what year any serial reads.

    The site now works out for itself how recent our Gibson records are, so the coverage note keeps pace with the data instead of having to be edited by hand each year.

    rules 08baeaa8 → 6fe14d02

69. 14 August 2026 · Squier · correction

    Stopped reading Korea-made KC and KV serials as instruments from decades that have not happened yet. A serial newer than the records we have checked now says so plainly instead of naming a guessed year.

    KC55 followed by five digits was being read as the year 2055. The two digits after the KC or KV prefix can only say where a year sits within its century, and this rule was allowed to run past the present day. Every year we give now has to fall within the years our sources actually verify, a limit that moves forward each time we refresh those sources.

    rules 93a1127b → 34135552

70. 14 August 2026 · Taylor · correction

    Stopped reading ten-digit serials as instruments from decades that have not happened yet. A serial newer than the records we have checked now says so plainly instead of naming a guessed year.

    Taylor's ten-digit format hides the year across the second and seventh digits of the serial, and those two digits together could point past the present day (for example, reading as 2082). Every year we give now has to fall within the years our sources actually verify, a limit that moves forward each time we refresh those sources.

    rules 53262c15 → 3823a649

71. 14 August 2026 · PRS · correction

    Stopped reading serials that start with a year we have not checked as if we knew the year. A serial newer than the records we have checked now says so plainly instead of naming a guessed year.

    A serial beginning 55 was being read as the year 2055, and an acoustic serial starting A55 the same way. Two digits can only say where a year sits within its century, and these rules were allowed to run past the present day. Every year we give now has to fall within the years our sources actually verify, a limit that moves forward each time we refresh those sources.

    rules 6ecf4f4d → a28c9d86

72. 14 August 2026 · Fender · correction

    Stopped giving confident years that have not happened yet. A Mexico or Indonesia serial whose two year digits point past the newest year our sources verify (some as far out as the 2100s) now comes back as a number we do not recognize.

    A serial beginning MX05 was being read as the year 2105, and one beginning MX45 as 2045. Two digits can only say where a year sits within its century, and these rules were allowed to run past the present day. Every year we give now has to fall within the years our sources actually verify, a limit that moves forward each time we refresh those sources.

    rules 1decff69 → 1611ebb1

73. 10 August 2026 · Fender · correction

    Indonesian-made Fenders are dated from the number that follows the factory letters. We used to accept either five or six digits after the two year digits; Fender only documents six. A shorter number, such as IC15 followed by five digits, was being read as a year. It now comes back as a number we do not recognize instead.

    Fender's own Indonesia page describes one shape: the factory letters, then an eight-digit number whose first two digits are the year. Nothing published shows a shorter one, so dating those numbers was a guess dressed up as an answer. If short Indonesian numbers do turn out to exist, we will carry them again once a second source shows one.

    rules 1be18e28 → 1decff69

74. 10 August 2026 · Gibson · refresh

    The two notes explaining which Gibson factory a ranking number points to are rewritten. The facts are the same: the Kalamazoo and Nashville bands before 1984, and Bozeman building the acoustics from 1989.

    We write every explanation ourselves rather than borrowing another site's wording, and these two sentences had drifted close to the phrasing of one of the sources we cite. Rewriting them keeps our own words our own. No serial decodes differently.

    rules 50959b10 → 08baeaa8

75. 9 August 2026 · Fender · correction

    Answering the S-prefix headstock question (United States or Japan?) used to leave the spec sheet's Country line reading 'United States or Japan, not separable from the serial alone' even after you had just told it which one. It now updates to say the country plainly (United States or Japan, whichever you picked) once you have answered.

    The rule that reads the S prefix genuinely cannot tell the two countries apart from the number alone, so the unresolved Country line was correct before you answered. It stayed wrong after you answered, because the answer was never written back into that line. Every reading this format can produce (both countries, and every way of narrowing to just one) is exercised by the automated test suite so this cannot silently regress.

    rules 57f57845 → 1be18e28

76. 9 August 2026 · Fender · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules 9b92e292 → 57f57845

77. 9 August 2026 · Gibson · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules a07d5a52 → 50959b10

78. 9 August 2026 · Martin · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules 349a4c40 → 324c36fb

79. 9 August 2026 · PRS · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules 5487ea68 → 6ecf4f4d

80. 9 August 2026 · Squier · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules 403f367f → 93a1127b

81. 9 August 2026 · Taylor · refresh

    Every decode rule now names the exact sources that back it, and each source carries a class such as manufacturer official or specialist reference, so the methodology page can show precisely what supports each era.

    Groundwork for community contributions. Linking rules to their sources lets the site show per-era sourcing and catch stale references automatically. No serial decodes differently than before.

    rules 48cfe8fb → 53262c15

82. 8 August 2026 · Gibson · correction

    The post-1977 standard format used to accept any three digits as the day-of-year (so a serial like 89999999 read back as a confident 1989, day 999 of the year) and let a leading-2 21st-century serial pair with any final year digit, including years that have not happened yet (a serial reading as 2029 came back confident). Both are fixed: the day-of-year digits now have to be a real day (001 through 366), and a leading-2 serial's year digit is capped at the current data year. The home page's Gibson coverage note now reads through 2026 instead of 'present', matching what the format can actually decode.

    Two gaps let implausible or not-yet-possible serials decode as confident answers, and the coverage note claimed open-ended coverage the format could not back up once the year pairing was capped. Also fixed: the single format that used to hold both the 1977-1979 and 1980-1999 readings declared the same capture-group names twice inside one alternation, which is only legal regex syntax on very recent browser engines; anything older threw a startup error and took down the whole lookup. It is now two formats, one per lead digit, the same split already used for the 2000s/2010s versus 2020s reading.

    rules 4128b1f2 → a07d5a52

83. 8 August 2026 · Fender · correction

    The Korea rule's own text said an instrument could date to the second half of 1993, but the answer never actually offered 1993 as one of the possible years: only 1994 through 1996. It now offers 1993 too, so the answer matches what the rule already said in its own explanation.

    Deep-review 2026-08-08 finding H3: the rule's prose and era label both named 1993 as in scope, but the candidate set silently dropped it, so a real 1993 Korea-made instrument was never told the correct year was even possible.

    rules 769e600d → 9b92e292

84. 8 August 2026 · Squier · refresh

    The Japan-era coverage label read '1982 onward' even though the run this table covers ends in 1984. It now reads '1982 to 1984', matching the actual end date already used everywhere else this era is dated. No serial decodes differently.

    Deep-review 2026-08-08 finding L-DA2: the label overstated how far this era's coverage runs.

    rules bbde434d → 403f367f

85. 8 August 2026 · PRS · refresh

    Removed two unreachable alternatives from the pre-1985 excluded era's match pattern: a three-digit branch and a leading-zero branch that a real serial can never reach, because the single-digit-prefix formats for those same digits always claim the number first. No serial decodes differently.

    Deep-review 2026-08-08 finding L-DA1: dead regex branches that could never fire, left in the data as if they still mattered.

    rules e6f73ccd → 5487ea68

86. 8 August 2026 · Fender · correction

    Answering the headstock question on a Japan-made Fender, or the country question on an S-prefix serial, used to come back with one confident year. It now comes back with the full run those numbers cover ('Made in Japan, 1985 to 1986', for example) at probable confidence, and it repeats what our source says about that run underneath.

    Fender does not break these runs down by year. Answering the question tells us which factory and which run the instrument came from, which is a real narrowing, but it does not pick a year out of the run, and the answer screen was claiming it did. Each of these readings now carries the run it actually covers, so nothing can quietly turn a four-year span into a single year again.

    rules b81530c4 → 769e600d

87. 6 August 2026 · Fender · refresh

    Fender's coverage-line entry now reads '1976–present' in a parenthetical, marking the deliberate pre-1976 coverage cut. No serial decodes differently; this is the home-page coverage sentence only.

    Gate B design response Ask 5 (Rule A): a parenthetical only where coverage deliberately starts later than the brand's history reads as information rather than boilerplate. Fender pre-1976 is exactly that cut.

    rules e28a280f → b81530c4

88. 6 August 2026 · Gibson · refresh

    Gibson's coverage-line entry now reads '1977–present' in a parenthetical, marking the deliberate pre-1977 coverage cut (the 1961–1975 era stays hard-excluded either way). No serial decodes differently; this is the home-page coverage sentence only.

    Gate B design response Ask 5 (Rule A): same as Fender: the parenthetical flags a scoping decision (pre-1977 not covered), not a derivation of every brand's span.

    rules e17dcaea → 4128b1f2

89. 6 August 2026 · Taylor · expansion

    Added the Taylor brand table. Taylor serials decode across three length-distinct formats (nine-digit for 1993–1999, eleven-digit for 2000–2009, and ten-digit from November 2009 onward), each reading the calendar year directly from the digits. Pre-1993 sequential numbering reads as unrecognized; the run had no year-encoded serials before 1993.

    Phase 2 brand expansion. Taylor encodes the manufacturing year explicitly in every supported serial, so every result is definitive with no ambiguity or disambiguation prompts. The ten-digit format exercises the non-contiguous yearDigits amendment (year at digit positions 2 and 7).

    rules 00000000 → 48cfe8fb

90. 6 August 2026 · Fender · expansion

    Added the Fender brand table. Covers US, Mexico, Japan, Korea, and Indonesia production per Fender's per-country official articles: decade-letter formats (US S/E/N/Z/US, Mexico MN/MZ/MX), reused Japan letters (A/O/P/Q/S/T) with a headstock-text disambiguation prompt, and the JV/SQ Japan prefixes. Pre-1976 US production routes to out-of-scope with a guide link; acoustics and amps are excluded eras.

    Phase 2 brand expansion. Fender's own documentation cautions that production-lag makes letter-prefix years inexact, so every reading ships at probable confidence rather than definitive. The Made-in-Japan vs Crafted-in-Japan letter reuse is the canonical same-year-different-factory case the candidate-id (not year) disambiguation exists for. Korea's incomplete records read as terminal ambiguity rather than a fabricated range.

    rules 00000000 → e28a280f

91. 6 August 2026 · Gibson · expansion

    Added the Gibson brand table. Post-1977 8- and 9-digit YDDDYRRR serials decode by reading the year from the 1st and 5th digits (non-contiguous positions), split into one format per century so the regex constrains plausible year digits. A lone century pivot would otherwise turn a garbage serial into a fabricated 2050. The 1994 Centennial carve-out is listed first. The 1961–1975 era is hard-excluded with its own guide: Gibson reused those serial ranges two to four times out of sequence and never published shipping records.

    Phase 2 brand expansion. The century split is required because resolveCentury has no per-pivot upper bound, so the match alternation is the only guard against an implausible-year-digit serial decoding definitively to a wrong year. The 1961–1975 exclusion is a hard rule (CLAUDE.md): anyone giving one year for that number is guessing.

    rules 00000000 → e17dcaea

92. 6 August 2026 · PRS · expansion

    Added the PRS (Paul Reed Smith) brand table. Pre-2008 set-neck serials carry a single leading year digit that repeats across decades, so each leading digit is a candidates rule: a '5' plausibly means 1985, 1995, or 2005, disambiguated by a sequential-number-range prompt. Post-2007 two-digit-prefix set-necks and the acoustic A-prefix format encode the full year and read definitive. SE-series instruments (letter-coded) and pre-1985 serials are excluded eras.

    Phase 2 brand expansion. PRS is the case the three-candidate ceiling exists for: a single digit genuinely spans up to three decades, and encoding that away would misstate the data. The candidates rule ships every candidate year; no candidate is ever promoted to definitive from the ambiguous set itself.

    rules 00000000 → e6f73ccd

93. 6 August 2026 · Squier · expansion

    Added the Squier brand table. Covers Japan (JV and SQ prefixes) and Korea (CN/VN decade-digit and KC/KV two-digit-year formats) per Fender's per-country articles, re-derived clean-room from the same sources Fender's table uses but as Squier's own table with its own provenance. The JV and SQ prefixes carry an authenticity caution at probable confidence. These are now collectible and a frequent target for reproduction decals and re-stamped plates, so the year is only as trustworthy as the instrument's authenticity. The NC Bullet era reads out-of-scope ('dating unclear' per Fender).

    Phase 2 brand expansion. Squier is a Fender brand sharing serial-format families with Fender, but ships as a separate table (own file, own provenance, own fixtures), with no cross-brand table sharing. Fender's own articles state Japan and Korea records are incomplete, so every Squier definitive year reads at probable, never definitive.

    rules 00000000 → bbde434d

94. 6 August 2026 · Martin · correction

    Refuting the Sigma-Martin reading on a serial between 900001 and 902908 used to hand back a definitive 2002 from the main numbering run. It no longer does; that block of numbers was never issued to a main-run instrument, so refuting Sigma now correctly says the number doesn't decode. Separately, a serial from a year newer than the chart we carry now says so directly instead of reading as an unrecognized number.

    Martin's own chart pins its footnote for that number range to the 2002 row specifically, meaning the main run skipped those numbers rather than reusing them once its count passed through that range in 2002. The table previously let the range chart claim the block anyway once the Sigma reading was ruled out, which produced a real year for an instrument that was never given one. The overflow change landed in the same update: the main-run chart has an end date, and a serial newer than that end date used to read exactly the same as an unrecognizable one, with no way to tell them apart.

    rules 36511eef → 349a4c40

95. 6 August 2026 · Martin · refresh

    The Sigma-Martin block's disambiguation prompt was rebuilt to track its two candidate years by a stable internal id instead of by the year value itself.

    This is an internal change to how the site represents an ambiguous reading, made so a future brand table can tell apart two readings that share the same year. It does not change what Martin decodes: every serial that read a given year, or the Sigma-Martin 1981-to-1982 range, decodes exactly the same way before and after this update.

    rules bdcdf8ea → 36511eef

96. 5 August 2026 · Martin · correction

    The main-run year reading was downgraded from a definitive answer to a probable one, and the reason for that moved from a supporting note into the line shown directly under the confidence meter, where it will actually be read.

    Martin numbers two of its other lines, Little Martin and Backpacker, on their own separate sequences, and those numbers can be identical to a main-run number across roughly 1929 to 1980. A current, inexpensive Backpacker was reading back as a confident vintage-year answer. The line stamped on the label inside the soundhole is what actually settles it, so every main-run result now says to check there.

    rules 2ea8ea49 → bdcdf8ea

97. 5 August 2026 · Martin · expansion

    Martin was the first brand this site could read, and this entry marks where its records begin. No serial reads differently because of it. Every Martin correction on this page sits above this line, and this is the state they all trace back to: the tables as they first shipped, before anything on this list had happened to them.

    This list is meant to read as an unbroken run. Each entry names the state of a brand's tables before it and after it, so the oldest entry for a brand should point back at nothing, because nothing came before it. Five of our six brands read that way from the start. Martin did not: the Martin tables were written before this list existed, so the oldest Martin entry pointed back at a state no entry here described, and a reader following it back ran out of list before running out of history. This entry closes that gap and makes no claim about any serial. The state it names is the Martin tables exactly as they were first committed, read back from that day's file rather than assumed.

    rules 00000000 → 2ea8ea49