Chess960

Also known as Fischer Random Chess.

White pawns are placed on the second rank as in standard chess. All remaining white pieces are placed randomly on the first rank, with two restrictions:
(1) The bishops must be placed on opposite-color squares.
(2) The king must be placed on a square between the rooks.
Black's pieces are placed equal-and-opposite to White's pieces.

Castling rules are modified.
- After a-side castling, the king finishes on c1 or c8 for Black, and the a-side rook finishes on d1 or d8.
- After h-side castling, the king finishes on g1 or g8 and the h-side rook finishes on f1 or f8.