>>49824862Alright I'm going to give a non-troll response.
All the games only get abbreviated by the first letter unless it has two words or there's a good reason to include the second name. For example, Sun/Moon is SM. SuMo is fucking dumb and literally made up by reddit because in their alternate reality they thought that google searches would bring up Sadism/Masochism and they thought that creating a different tag would help the kiddos, but when a later game was literally one letter off from BDSM nobody said shit.
Following this logic, Ultra Sun/Ultra Moon is USUM not USuUMo.
Sword/Shield is SWSH, but this is only because SS was already taken by Soul Silver in HGSS so the abbreviation is for clarity. I would have preferred S&S but it never caught on.
Brilliant Diamond/Shining Pearl is BDSP as said above.
And Scarlet/Violet is SV. No two letters, nothing like that is necessary, and if for some reason there happens to be a second pair of games in the region it would be best to not have three letters for each version.
