The serial number of a Korg M1 can be significant for several reasons:

When ordering parts from Korg (or third-party vendors like Syntaur or Instrumental Parts), you need your serial number to determine which revision of a part you have.

The Korg M1, released in 1988, is widely considered the first true music workstation

If you find an M1 with no serial number, proceed with extreme caution. It is likely either a very rare collectible (if it has other prototype traits, like a different case color or silkscreening) or, more commonly, a unit with a dubious history involving theft or unlicensed repairs.

Korg transitioned its numbering system in 1983. For the M1 era (1988–1995), the serial numbers are (usually 6 digits) and do not contain embedded date codes like "YYMM". Instead, dating is determined by comparing your number to known production milestones: