The first letter indicates the last digit of the year of production. Tenryu/Wada Factory, Made in Japan, 1985-1986: ######.
(Their numbering system began with “H” for 1.) The second letter indicates the month.
The letter at the beginning represents the month, so J would be March (see chart above). Custom Shop, Made in Japan, 1991-1996: Letter-letter-###-letter, like so: HP213J. 111 is the unit number; and the final letter is an internal code. During 1999, they starting the count each month at 200 rather than 500. Tenryu/Wada Factory, Made in Japan, 1946-1968: #####.
The first two numbers (07 in this example) are the day; 7th. Made in Taiwan, 2002-: Letter-letter-letter-######, like so: QJM120013. The first two letters are the year; QK=04 (see chart.) The third letter is the month; J=March. Made in Korea Made in China, 2003-: Letter-letter-letter-####-letter, like so: QKJ0011Y.Example: hm02316 = the 316th unit made on June 2 of 1961, 1971, 1981, 1991, or 2001. If you still can’t figure it out, please see Yamaha contact info at the bottom of this page. Tenryu/Wada Factory, Made in Japan, 1969-1984: ######. Custom Shop, Made in Japan, 1966-1985: 001-1042 in sequence Custom Shop, Made in Japan, 1986-1990: Letter-####, like so: J7012. The first two numbers indicate the day of the month.
The last three numbers represent order of production on the day the guitar was made. ” To you folks, we offer the following: Several other serial number configurations used by Yamaha over the years. Martin also built mandolins (introduced in 1895), ukuleles (introduced in 1915), taropatches (an 8-stringed ukulele), tiples (a 10-stringed ukulele), Hawaiian guitars, and tenor banjos (in 1923) plus a few custom instruments. Zoebisch & Sons was the exclusive distributor of all Martin instruments, and that name appears on a paper label inside the sound hole. Beginning in 1929 the model numbers were marked on the neck block, inside the body. The second and third numbers are the month; March (03). The third letter is the month; June (see chart above.) The first and second numbers (following the 3 letters) are the day; 18th. Made in Japan, 1984-1986: Letter-letter-letter-letter-###. The next letter (3rd position) is the month; in this case M=June (see chart.) The final three numbers are the unit number. the letter (3rd position) is the month; March (see chart.) The final four numbers are the unit number; 13.