Melodeons and diatonic boxes — Hohner, Castagnari, Saltarelle — mostly lack public serial tables: dating follows the reed-plate eras, bellows patterns and, on later Castagnaris, the date written under the grille.
Usually on the inner face of the treble end or on the reed-block frame — some makes carry no number at all. 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.