Is there a reason why the set abbreviations went from 3 letters/numbers to 4?

[Deathjester]

Just strikes me as somewhat odd that they made that change...

 

[djp952]

They did it in Japan for Series 5, so we followed suit. Over the course of the game, they've gone from no code at all, to a 2+2 (code/number), to a 3+3 (code/number), to a 3+2+3 (code/language/number), and now a 4+2+3 (code/language/number).

My best guess as to why would be things like LEx (in Japan) and DLx (here), where they hit "9" and unless they switched to using Hexadecimal, they just needed more room.

I don't think there is a whole lot of "reason" in it, just a necessity.

I just wish they wouldn't do it for existing sets like SP2 and JMP. (edit: and apparently SJC now.) Kinda messes up RONIN since it links on the set codes.

 

[Blue-Eyes Black]

I'd say it was necessity on two fronts, with UDE considerations first.

1) We were reaching the end of our Duelist League series (DL#-EN###). We already had DL9-EN001, Last Day of Witch. We couldn't release another card without changing the numbering scheme.

2) Japan is getting ready for their 10th Structure Deck. Had we not hit the Duelist League problem, the renumbering might have been delayed to Cyber Dark Impact's release rather than Power of the Duelist's.