Guides

Reading a Martin soundhole stamp

Martin has used a single run of serial numbers since 1898, which makes it the most dependable system in this tool. It is also the one where small details change the answer, so it helps to read the stamp carefully.

Finding it

Look inside the body, through the soundhole, at the centre block, the wooden strip running down the middle of the back. The serial is stamped there, and it is also stamped on the neck block. A small torch and a mirror make this far easier than guessing. Hold the instrument so light falls through the soundhole onto the block, and look from the side rather than straight down.

Numbers stamped before 1898 are a separate, earlier problem. Anything below 8349 is read as 1898 or earlier, so the tool tells you the number is early but gives no single year.

Reading the number

Write the digits down exactly. Martin numbers are plain digits with no letters, up to seven. Type them into the decoder with the Martin chip selected. The result is the year in which the highest serial reached that figure. For example, the published example 117961 reads as 1954 in the decoder.

How the years are assigned

Martin recorded the last serial number of each year. A guitar belongs to the year in which its number falls at or below that year-end figure. Two things follow.

First, a guitar finished early in a year may carry a number that sits close to the previous year-end. If your number is near a boundary, the guitar could be from the earlier year or the later one, depending on when in the year it was stamped. The decoder shows the last serial of that year in the rule detail so you can see how near you are.

Second, the figures are a record of production and not a guarantee of when a given guitar was finished. Treat the year as the best reading, and check it against features.

The 1956 doubt

The two main published sources give different year-end figures for 1956: 152775 and 153225. A serial in that gap could be 1956 or 1957, and the decoder says so rather than choosing. If your guitar falls there, look at features and the tooling. Do not trust a single year.

Sigma-Martins

Serials 900001 to 902908 belong to Sigma-Martin instruments from 1981 and 1982. The Martin year table does not apply. The decoder does not decode them as Martins.

Instruments the chart does not cover

Martin kept separate charts for some models, including the LX and Backpacker ranges, and for some ukuleles and mandolins. That data is not yet in this tool. See dating ukuleles, banjos and mandolins and the About page for known gaps.

Checking the year with features

After you have a year, test it against a physical clue.

• Brazilian rosewood back and sides on standard models end by 1969. Tight straight grain with strong colour variation is typical of Brazilian, while Indian rosewood is plainer and more uniform.
• Herringbone top purfling on D-28 style models runs from 1931 to 1946.
• Scalloped top braces run from 1938 to 1944. You can see them with a mirror inside the body.
• An adjustable truss rod is standard from 1985, shown by a hex nut visible at the soundhole end of the neck.

If the serial says 1954 and the guitar has an adjustable truss rod, one of them is wrong, and the rod is likely a later change. If the serial says 1941 and the braces are not scalloped, that is worth a closer look at the guitar, not a conclusion.

This guide dates an instrument. It does not value it or authenticate it. A serial is evidence, not proof.

Related

• Martin brand page and decoder
• Dating by features
• Serials that lie