Chess Special Moves: Castling, En Passant and Promotion

Most of chess is simple to learn: each piece moves in its own way, and you win by checkmating the king. Then a few rules surprise almost every beginner. “You can’t castle there.” “That pawn just took mine sideways?” “Why is it a draw, I have a queen?” This guide explains the three special moves and the draw rules that catch people out.

Castling

Castling is the only move in which two pieces move at once. It gets your king to safety and brings a rook toward the centre.

How to castle

Move the king two squares toward one of your rooks. The rook then jumps to the square the king just crossed.

Side	King moves	Rook moves
Kingside (short), White	e1 to g1	h1 to f1
Queenside (long), White	e1 to c1	a1 to d1
Kingside (short), Black	e8 to g8	h8 to f8
Queenside (long), Black	e8 to c8	a8 to d8

On a screen, you usually castle by moving the king two squares; the rook follows automatically.

When castling is not allowed

You may not castle if:

1. the king has moved earlier in the game, even if it moved back;
2. that rook has moved earlier in the game;
3. any square between the king and the rook is occupied;
4. your king is in check right now;
5. the king would pass through a square attacked by an enemy piece;
6. the king would land in check.

The rook is allowed to be attacked, and on the queenside it may pass through an attacked square (b1 or b8); only the king’s path matters.

En passant

En passant (French for “in passing”) is a pawn capture that only exists right after a pawn’s two-square first move.

How it works

A pawn on its starting square may move two squares forward. If that move lands it directly beside an enemy pawn (on the same rank), the enemy pawn may capture it as if it had moved only one square: the capturing pawn moves diagonally onto the square that was skipped, and the pawn that moved two squares is removed.

Example: a white pawn stands on e5. Black plays d7 to d5, landing beside it. White may now play e5 takes d6 en passant; the black pawn on d5 is removed.

The one-move rule

The capture must be made on the very next move. If you play anything else, the chance is gone for good. En passant is only possible for pawns, only against a pawn that has just made a two-square move, and only from the fifth rank (for White) or fourth rank (for Black).

Pawn promotion

When a pawn reaches the far rank (the 8th for White, the 1st for Black), it must be promoted: replaced by a queen, rook, bishop or knight of the same colour.

• You may choose any of the four, regardless of what is already on the board. Two or even three queens are legal.
• You cannot keep it as a pawn or turn it into a king.
• Promoting to something other than a queen is called underpromotion. It is occasionally the only winning move, for example a knight promotion that gives check, or a rook to avoid stalemate.

Check, checkmate and stalemate

• Check: your king is attacked. You must get out of check on your move, by moving the king, blocking or capturing the attacker.
• Checkmate: your king is in check and nothing gets it out. The game is over and the attacker wins.
• Stalemate: it is your move, your king is not in check, but you have no legal move. The game is a draw.

Stalemate is the classic beginner trap: with a big material advantage, you take away every square from the enemy king without giving check, and half a point vanishes. When you are winning, always check that your opponent still has a move.

Other draws

Draw	When it happens
Threefold repetition	The same position occurs three times with the same player to move
Fifty-move rule	Fifty moves by each side with no capture and no pawn move
Insufficient material	Neither side can possibly checkmate, for example king against king, or king and bishop against king
Agreement	Both players agree to a draw

Five rule myths

• “You can’t castle after being checked.” You can, as long as the king and that rook have not moved and you are not in check right now.
• “A pawn can only promote to a captured piece.” No: any queen, rook, bishop or knight, whatever is still on the board.
• “The king can’t move next to the enemy king in check.” Kings can never stand next to each other at all, because each would be in check.
• “Running out of time with a bare king loses.” In timed games, if your opponent has no way to checkmate, running out of time is usually a draw.
• “Touching a piece is fine in casual play.” In tournaments, a piece you deliberately touch must be moved if it has a legal move.

Practise the special moves

The chess game on this site follows every rule above: castling (never out of, through or into check), en passant, promotion to queen, rook, bishop or knight, stalemate, threefold repetition, the fifty-move rule and draws by insufficient material. Legal moves are shown as dots when you select a piece, so you can see exactly when castling or en passant is available.