Chess960 (Fischer Random Chess)

How the Rules Change

• The back-rank pieces (not the pawns) are arranged in one of 960 possible random starting positions instead of the standard setup — hence the name.
• Two constraints are kept from standard chess: the bishops must end up on opposite-colored squares, and the king must start somewhere between the two rooks (so castling is still possible).
• Castling rules are adapted to work from any legal starting square: the king and the chosen rook still end up on their normal standard-chess castled squares (g1/f1 or c1/d1, and the mirrored 8th-rank squares), regardless of where they started.

History

Bobby Fischer, the 11th World Champion, invented and publicly proposed the variant in 1996, explicitly to reduce the growing advantage of players who could simply memorize more opening theory than their opponents rather than out-play them from the earliest moves.

It has since grown into a serious, officially recognized discipline — FIDE has run a Chess960 World Championship, and elite players including Magnus Carlsen have competed in dedicated events.

Why Play It

It restores the sense of having to actually think from move one, since no amount of memorized theory can prepare a specific reply to a starting position nobody has seen before that day.