I've been researching the Super Mario Bros European Version variants for NES. I have pretty much completed the research I can and have made this sheet
https://docs.google.com/spreadsheets/d/1NyrzKmPzTLag1kGahkApsSvcG9NUnaPFGzb_jpPMbTI/edit?usp=sharingIf I add only the ones marked in green (or the y/z entries) I figured out I can name them like so:
18369 (European Version / black Seal) [DE]
z1 (European Version / black Seal) [FI]
z2 (European Version)
z3 (European Version / white circle Seal)
z4 (European Version / white oval Seal)
125943 (European Version / Action Series) [FI]
y1 (European Version / Action Serie / FRG manual)
y3 (European Version / Action Serie / FRG-1 manual)
y4 (European Version / Action Series) [GR]
y5 (European Version / Action Series) [PT]
However, the ones marked with x are not confirmed as far as the box combinations, however it does include carts that are not accounted for.
x1 NES-SM-EEC / FRG
x3 NES-SM-SCN / SCN
x4 NES-SM-EEC / na
I'd like to hear any ideas about how to handle the x listings. I may end up just not adding those at this time which would probably be the easiest option.