How to play Chess960: setup, castling, and your first game
Chess960 is chess with the pieces on the back rank shuffled. If you already play chess you can play it this afternoon. There is one rule to relearn, and it is castling.
The one paragraph version
It is chess. Pawns, captures, check, en passant, promotion, the fifty move rule, all of it unchanged. Before the game a number from 0 to 959 is drawn, and that number fixes where White's eight pieces stand on the first rank. Black's pieces stand on the same files. The pawns sit on the second and seventh ranks and are never touched. Castling still exists, and the king and rook still finish on g1 and f1 short, or c1 and d1 long, from wherever they started. That is the game. If you read nothing else on this page you can now play.
Both players get the same arrangement, so nothing is being done to you that is not being done to your opponent. The rules page states the same thing in full, including why the arrangement has to obey two constraints.
How do you set up a Chess960 board?
Get a position first. Draw a number from the position generator, or let an app deal one, or roll dice against a chart. Every legal arrangement has a number between 0 and 959, and 518 is ordinary chess.
Then set White's first rank left to right as printed, a1 through h1. Then copy it to Black on the same files. White's queen on a1 means Black's queen on a8. White's king on g1 means Black's king on g8.
That second step is the one people get wrong, and they get it wrong in a specific way: they read White's rank left to right and lay Black's out right to left, as though rotating the board. The result is a legal looking position that is a different game, and it is not the same game for both players.
QNBBNRKRQNBBNRKRTwo checks catch it. Every white piece faces its own kind down a file, queen on queen, king on king, exactly as in ordinary chess. And the position obeys the same two constraints on both sides: the bishops stand on opposite colours, and the king stands somewhere between the two rooks. The board above is position 5 if you want to set it up and check yourself.
How do you play Chess960 online?
Sites use both names. Lichess lists the variant as Chess960; Chess.com calls it Fischer Random. It is the same game with the same numbering, so a position 518 on one site is a position 518 on the other.
Online you cannot set it up wrong, which removes the mirroring problem entirely. What you have to learn instead is how the interface takes a castling move. Most boards accept dragging the king onto your own rook. Some also accept the king moving two squares toward the rook, which breaks down when the king already stands on g1 and has nowhere to go, so the king onto rook method is the one to use everywhere. It works against the computer here as well.
What changes about castling?
The destinations never change. Castle short and the king ends on g1 with the rook on f1. Castle long and the king ends on c1 with the rook on d1. Everything between the two pieces and their destinations must be empty, neither piece may have moved, and the king may not start in check, pass through check, or land in check.
QBNRNKBRWhat changes is how far each piece travels, which is different in every position. In some arrangements the king moves one square, in others five. In some the rook is already sitting on its destination, so only the king moves, and on the board it can look as though your opponent has made an illegal move. The full set of cases, including the position where the king and rook swap squares, is on the Chess960 castling page.
What do you play on move one?
You have no theory and neither does your opponent, so spend the first thirty seconds looking at your own back rank rather than his.
Find the bishop that has nothing to do. One of your bishops usually has a diagonal waiting behind a pawn, and the other is walled in. The pawn move that opens the good one is a strong candidate for move one. A bishop starting on a1 or h1 is the clearest case: play the b pawn or the g pawn one square and the bishop owns the long diagonal at the cost of a single move, as in position 16 below.
BBNQNRKRThen count your castling. How many pieces sit between your king and g1, and between the kingside rook and f1? Do the same for the queenside. One of those counts is usually much smaller, and that is the side you are castling to, which tells you where the rest of your pieces should be going.
Then play a central pawn to a square you have played it to a thousand times, and develop a knight. The pawns start where they always start, so every structure you know is still reachable. Do not try to force the position into your favourite opening; you will spend three moves buying a shape the pieces were never standing in. The longer version of all this is on the strategy page.
Three things that surprise people in their first game
The first is a castling move that looks illegal. Your opponent castles and only one piece moves, or the king travels rightwards to castle long. Both are legal and both are common.
The second is that you will hang something. Not to a clever idea, but to a piece standing somewhere your eye has never had to check. A bishop on h1 sees a8. A queen on b1 sees the whole queenside and half of the rest. Your pattern memory is filed by square, and the filing is temporarily wrong.
The third is the pawn in front of the corner. In 600 of the 960 arrangements at least one pawn on your second rank has no defender at all when the game starts, and it is usually a2 or h2. In ordinary chess a rook defends that pawn from move one. Here it may be defended by nothing, with an enemy bishop pointing at it by move three. Which positions those are is counted on the page about the positions themselves.
Where to play and practise
Play the computer from a random position. Ten games is enough for the setup and the castling to stop being what you are thinking about, at which point you are playing chess again, in an unfamiliar coat.
Deal yourself positions in the generator and read the back rank without moving anything: where the king castles to, which pawn is weak, which bishop is buried. Thirty seconds each. It is the cheapest training there is.
For the part principles cannot help with, which is seeing a fork delivered from b1 when your eye has only ever filed forks from f7, use the Chess960 puzzle trainer, or the books if you want a thousand of them on paper.