What makes these three moves special?
One king move, two pieces changing squares
For White, kingside castling ends with king g1 and rook f1; queenside ends with king c1 and rook d1. Black uses g8/f8 or c8/d8. Move the king first and use one hand. Touching the rook first does not reserve a right to castle with it: Article 4.4.2 applies.
Watch the first move for White’s kingside castle, then the second for Black’s queenside castle. Pay attention to both pieces, not only the king.
Scroll the table sideways to compare all columns.
| Check | What must be true? | Easy mistake |
|---|---|---|
| History | This king and the participating rook have never moved | Returning them to their starting squares does not restore the right |
| Empty path | Every square between king and rook is empty | Queenside castling also needs b1/b8 empty |
| King’s route | Starting, crossing and destination squares are not attacked | Castling cannot be used to get out of check |
| Rook under attack | This alone does not forbid castling | The king-safety restriction does not apply to the rook in the same way |
These are cumulative conditions: passing three checks does not excuse failing the fourth. Article 3.8.2.
Blocked for now, or forbidden for the rest of the game?
If your bishop is still on f1, moving it may clear the way for a later castle. If your king has already left e1 and returned, no move can restore either castling right. A rook move loses the right involving that rook. This distinction explains why two identical-looking boards can have different legal moves.
In the example, Black’s rook attacks f1. White cannot castle through f1, even though g1 is safe. The replay shows the legal alternative: queenside castling. If the attack on f1 later disappears, it removes that obstacle, provided the relevant king and rook have still never moved.
Article 3.8.2.1 covers losing the right; 3.8.2.2 covers temporary prevention. A pinned enemy piece still attacks squares for this purpose.
En passant: act on the very next move
Black advances d7–d5 alongside White’s pawn on e5. White may immediately play exd6, removing the pawn on d5 as if it had advanced only to d6. White’s King must remain safe. Articles 3.7.3.1–3.7.3.2.
Declining the capture closes the window. Here White moves the King instead; after Black’s reply, exd6 is no longer available. The pawn still being on d5 does not preserve the right.
Choose the piece that gives the result you want
A pawn reaching the farthest rank must become a queen, rook, bishop or knight of the same colour as part of that move. The new piece acts immediately. It need not be a previously captured piece: two queens are allowed. Articles 3.7.3.3–3.7.3.5.
Try a7–a8 below, then reset and try each choice. In this particular position, a queen or rook gives checkmate; a bishop or knight leaves a dead position and a draw. The lesson is not “always pick the queen”: in other positions an underpromotion can avoid stalemate or supply a needed knight check.
On a physical board, do not press the clock with an unpromoted pawn still on the last rank. If the piece you need is unavailable, pause the clock and ask the arbiter for assistance under 6.11.2. The illegal-promotion procedure is explained in the next tournament guide.
Try all four promotions
Select the highlighted piece, then a marked square to try a move.
FAQ
Can I castle through check if the King ends safely?
No. The King’s starting, crossing and destination squares must all satisfy the attack restriction. An attacked Rook is a different question.
Can I postpone en passant or leave a pawn unpromoted?
No. En passant is available only on the move immediately following the double advance. Promotion is part of the pawn’s move to the last rank, not an action reserved for a later turn.
Does an attack on b1 prevent White from castling queenside?
Not by itself. In ordinary chess b1 must be empty, but the king travels from e1 through d1 to c1. The attack restriction concerns the king’s starting, crossing and destination squares. All the other castling conditions must still be met.
Related rules
Sources and scope
FIDE Laws of Chess · 2023 · 3.7.3.1–3.7.3.5; 3.8.2; 4.4–4.7; 6.11.2.
Effective 1 January 2023. These guides explain over-the-board play. The official text and any event regulations permitted by it govern competition; teaching positions are not tournament records.