Shuffle

[Dave Neve]

Hello

I have quite a few questions about SHuffle.

1 What is the difference between shuffle and Fisher random chess?
2 Why can some engines apparently not play Fisher but can play shuffle?
3 I got stuck with shuffle some time after castling. Winboard showed me legal moves when I clicked on my queen, but would not let me make one of these moves (illegal move)?
4 Any other stuff that I should know about shuffle but didn't ask?

Thanks

[H.G.Muller]

Shuffle Chess is a general term for all variants that do not have a fixed position. Actual variants can differ by how exactly they shuffle the positions. I think that on freechess.org there are four shuffle variants (called wild/1 to wild/4); the most conservative of those ('wildcastle') puts the Kings on the d- or e-file, leaves Rooks in place, and shuffles Q, B and N over the remaining squares. Castling rules are reflected when the King starts in the d-file.

Fischer Random Chess (aka Chess960) is a special form of shuffle chess, where King and Rooks can also be shuffled. But only such that the King stays between the Rooks. For non-stadard positioning of King and Rooks there are then special castling rules ('Fischer castling').

Engines that do not know the special Fischer castling rules will not be able to play FRC. In wildcastle K and R start often in their normal locations; with the King on the e-file it is not really a variant, but just normal Chess starting from a non-standard position. So engines have no trouble to play that.

If WinBoard and the engine do not agree about the rules, it can happen that WinBoard allows you to enter moves it considers legal, but that the engine then rejects those as illegal.

WinBoard has a "New Shuffle Game" dialog that would allow you to play every chess variant as shuffle game; the way it shuffles the pieces depends on whether that variant had Fischer castling, normal castling or no castling at all.

[Dave Neve]

Wow, that's a lot to take it but thanks