The piano accordion is the most common free-reed instrument in the archive — mid-century instruments change hands constantly, and the maker matters: Hohner serials can be estimated from community data, while the Italian houses are dated by features. The number usually sits on the rear of the treble side or on the bass panel.
On the rear of the treble side, the bass-side panel or a small name plate — the exact spot moved over the decades. Markings and exact positions vary by maker and era — the serial number guide covers the common locations for every instrument.
2 makers with 202 dating ranges are listed on this page. Coverage grows as more maker records and historical tables are verified.
Recheck the characters exactly as marked — letters and leading zeros are part of the number. On several makes the stamped numbers are internal assembly or importer codes that cannot be dated; some production periods are simply not covered yet.