You will often see listings for the "Korg M1 EX." This is not a different serial number range.
The M1 EX was a factory upgrade or a DIY expansion board that doubled the internal preset memory (from 100 to 200 sounds) and added 18 new PCM waveforms. If your Korg M1 serial number is below 100,000, it almost certainly does not have the EX board. If your serial number is above 350,000, it likely shipped from the factory with the EX board already installed. You can verify this by turning on the M1 and looking for "EX" in the top right corner of the LCD screen.
While the vast majority of M1s bear a standard Japanese serial number (often printed on a white or silver sticker), a notable subset exists with a different format. These are the units assembled in Italy by Korg’s then-distributor, Korg Italy (formerly Sisme) , to meet overwhelming European demand. These Italian-made M1s often have serial numbers with an "I" prefix or a different numeric range, and they typically lack the "Made in Japan" stamp on the rear panel, instead reading "Made in Italy" or "Assembled in Italy." Korg M1 Serial Number
For collectors, Italian units are sometimes considered slightly less desirable due to minor component variations (e.g., different keybed manufacturers), but functionally they are identical. Their serial numbers are crucial for identifying the instrument’s intended market and assembly origin.
These units (produced late 1989 to early 1990) represent the "sweet spot." You will often see listings for the "Korg M1 EX
Always ask the seller for a photo of the serial number and compare it to known stolen gear databases (e.g., Stolen Guitar Registry, SynthFinder). Also check:
If you are selling your M1, the serial number should be the third line in your ad (after "Working" and "No smell"). Pro Tip: A working M1 with a dead
Pro Tip: A working M1 with a dead internal battery (the "Please install battery" error) is worth about $100 less regardless of serial number. Fixing this requires soldering.
The Korg M1 contains an internal CR2032 lithium battery that preserves user patches and settings.
The serial number of the Korg M1 is crucial for several reasons: