The king moves two squares towards the rook, and the rook jumps over it and lands on the other side, right next to it. Both movements are one move, not two: the opponent replies after both of them.
The point of the move is twofold. The king leaves the centre, where it is easier to attack, and hides behind a wall of its own pawns. And the rook, which normally sits idle in the corner throughout the opening, reaches a central file and joins the game. One move solves two problems at once - which is why players castle in almost every opening.
Kingside castling goes towards the near rook - the one on h1 for White and h8 for Black. There are only two squares between king and rook, so it is quicker to prepare: you only have to move the knight and the bishop.
For Black it is all mirrored, on the eighth rank. It is worth looking at it once through Black's eyes: on a board, «to the right» means opposite directions for the two sides.
Queenside castling goes towards the far rook - a1 for White, a8 for Black. The king still travels two squares, but the rook covers three - hence the alternative name, long castling.
The practical difference: preparation takes longer - knight, bishop and queen all have to move - and the king ends up on c1, slightly closer to the centre. The square b1 is left uncovered by the rook, so the first thing players often do is tuck the king away with Kb1 after castling.
At a tournament this is not a detail: the order of actions is fixed by the rules, and getting it wrong can leave you with a move you did not intend.
The touch-move rule and the other tournament details are covered in the rules of chess.
There are exactly four restrictions. The first two are about pieces, the second two about the king's safety.
The right is lost for good and does not come back, even if the piece returns to its original square. The rooks count separately: once the h1 rook has moved, kingside castling is gone but queenside remains.
Any piece - yours or your opponent's. Every square between them must be empty: two for kingside, three for queenside.
You cannot castle out of check. First block the check, move the king or capture the attacker - and if the king itself did not move, the right to castle survives.
The king may not cross a square that is attacked, and may not arrive on one. Both squares on its route have to be checked: f1 and g1 for kingside, d1 and c1 for queenside.
Two cases cause most of the mistakes at the board - and both times people forbid more than the rules do.
The restrictions concern the king and the squares it travels through. The rook may stand under attack, and it may cross an attacked square - none of that affects the right to castle.
The king travels e1 → d1 → c1 and never touches b1 at all - only the rook passes through it. So an attack on b1 does not prevent queenside castling.
And one more: being checked does not destroy the right. Only moving the king does. If you managed to block the check with another piece, you can still castle later.
A simple way to remember how many zeroes go where: there are as many as there are squares between king and rook before the move - two for kingside, three for queenside. How to keep a scoresheet in general - chess notation and scoresheets.
In computer UCI notation castling is written simply as a king move: e1g1 or e1c1. That is why engines and board editors show it as a single pair of squares, with no rook involved.
There are no rules here, only considerations. Kingside is faster and safer, queenside is more aggressive.
| Kingside (0-0) | Queenside (0-0-0) |
|---|---|
| Ready sooner: two squares to clear | Ready later: three squares to clear plus the queen to move |
| King further from the centre, pawns untouched | King on c1; b1 usually needs one more move |
| Rook lands on f1 - useful when attacking f7 | Rook lands straight on d1 - pressure down the central file |
| The usual choice in quiet positions | The choice when you plan a pawn storm against the enemy king |
A story of its own is opposite-side castling: one player goes right, the other left. Then each keeps the pawns in front of his own king and throws the rest at the opponent's - the game becomes a race of attacks, and tempo matters more than material.
A practical rule for beginners: castle within the first ten moves and do not put it off. A king stuck in the centre with the files opening is the most common cause of quick losses.
In Fischer Random (Chess960) the pieces on the first rank start in a random order, but castling exists there too - and the final squares are exactly the same: the king ends up on g1 when castling kingside and on c1 queenside, with the rook on f1 and d1 respectively.
It looks strange from the outside: king and rook can start almost anywhere and appear to teleport onto their squares. The conditions are the usual ones - the king has not moved, the rook has not moved, and the squares between them and along the king's route are empty and not attacked. The full picture - Chess960 (Fischer Random).
The only move in which two pieces of the same colour move at once: the king and a rook. The king shifts two squares towards the rook, and the rook jumps over it and lands beside it. It counts as a single move.
The side of the board. Kingside castling (0-0) is towards the h-rook: the king goes to g1 and the rook to f1. Queenside castling (0-0-0) is towards the a-rook: the king to c1, the rook to d1. Black does the same on the eighth rank.
In four cases: the king or that particular rook has already moved; there is a piece between the king and the rook; the king is currently in check; or the king would pass through an attacked square or land on one.
Yes. The restrictions apply only to the king and the squares it travels through. An attacked rook, and an attacked b1 square when castling queenside, are no obstacle at all.
Yes, provided the king itself did not move. Once the check is dealt with, the right to castle remains. But if the king had to move, the right is gone for good, even after it returns to e1.
One hand, and touch the king first. FIDE rules require the move to be made with a single hand; if you pick up the rook first, the arbiter may rule that you have moved the rook.
Kingside is 0-0, queenside is 0-0-0. In English notation the letter O is used: O-O and O-O-O. The number of zeroes matches the number of squares between king and rook before the move.
Once. After castling the king counts as having moved and the right disappears - even if the pieces are later returned to their original squares.
There are no club or arbiter roles in the app: the create button is available to everyone. You can announce a tournament today and run it this weekend.
The bot is constantly improved based on real tournaments. If you need a feature that isn't there yet, message the developers right inside the bot with the /support command. Many features appeared exactly because organizers asked for them, and useful ideas get added quickly.
All the rules - how to play chess. The starting position - setting up the board. Terms - chess glossary.
At the board since childhood: hazy about his rating, precise about every rook he has blundered. Counts an evening as a good one if the opponent stayed to talk afterwards instead of rushing off to check with an engine. Message →
