Chess960
The starting position of the home rank pieces is randomised.
Also called Fischer Random, after Bobby Fischer, who proposed it in 1996.
The rules
Ordinary chess, with one change: the back rank is shuffled before the game
starts. Both sides get the same arrangement, so the position stays symmetrical.
Two constraints keep it playable:
- the two bishops must stand on opposite-coloured squares
- the king must stand somewhere between the two rooks
That leaves exactly 960 starting positions, one of which is ordinary chess.
Castling still exists, and still ends with the king and rook on the usual
squares — king on c1/g1, rook on d1/f1 — however far they have to travel to get
there. The squares between must be empty, and the king may not pass through
check, as usual.
Why play it
Opening preparation is worth almost nothing. You cannot memorise 960 opening
books, so from move one you are working out the position rather than recalling
it. Fischer's argument was that this returns chess to a game of ideas.
What to watch for
Undefended pieces. In the standard array every piece is developed behind a
familiar wall; in Chess960 a rook or bishop can start out attacking something,
and a knight on b1 might already be hanging. Check what is loose before you plan
anything.