What happens after an illegal move?
Identify the incident before applying a penalty
Scroll the table sideways to compare all columns.
| Situation | Valid or invalid? | Arbiter’s response | Reference |
|---|---|---|---|
| King left in check, then clock pressed | Completed illegal move | Restore the preceding position; apply 7.5.5 | 7.5.1 |
| Castle across an attacked square, then press | Completed illegal move | Restore; the replacement still obeys touch-move | 3.8.2; 7.5.1 |
| Pawn left on the last rank, then press | Completed illegal move | Replace it with a Queen of the same colour; apply 7.5.5 | 7.5.2 |
| Press without making a move | Treated as an illegal move | Apply 7.5.5 | 7.5.3 |
| Two hands used for one move, then press | Treated as an illegal move | Apply 7.5.5, including castling/capture/promotion | 7.5.4 |
| Accidentally knock pieces over | Displaced pieces | Restore in the responsible player’s time; a penalty is possible | 7.4 |
The teaching board refuses illegal destinations. That is a learning aid, not a tournament penalty: a refused click is not a completed over-the-board illegal move.
Inspect the attacked square
Black’s Rook attacks f1. White’s kingside castling would cross it and is illegal. Queenside castling remains legal here; the replay shows that alternative, not an illegal move made to look valid.
If an illegal move has actually been completed, restore the position immediately before it. If that position cannot be established, use the last identifiable earlier position. Articles 4.3 and 4.7 still constrain the replacement. The arbiter adjusts time and the clock’s move counter using the evidence; Article 7.1 also permits leaving the displayed times unchanged.
The second offence means the same player’s second offence
Consider a game using the main Competitive Rules. White completes an illegal move: after correction, Black receives two minutes. Later Black completes an illegal move: White receives two minutes. Neither player has yet committed a second offence.
If White then completes another illegal move, it is White’s second. Article 7.5.5 requires a loss, except that the result is a draw if Black cannot checkmate by any possible legal sequence. The number of offences is not a shared counter for the entire game.
In rapid, and blitz under B.3, the applicable time addition is one minute. The correction and the distinction between a first and a second offence still matter. Before deciding a penalty, check both the format and whether the opponent’s next move has closed the A.5 claim window.
Setup errors are not all restarted
Scroll the table sideways to compare all columns.
| Error | Main-rule remedy |
|---|---|
| Incorrect initial arrangement of pieces | Cancel and play a new game: 7.2.1 |
| Board rotated with the wrong corner colour | Transfer the current position to a correctly oriented board: 7.2.2 |
| Players started with reversed colours | New game if both have made fewer than 10 moves; after 10 or more, continue: 7.3 |
| A piece later found displaced | Restore the pre-incident or last identifiable earlier position: 7.6 |
Under A.5, after each player has completed 10 moves, incorrect initial setup or board orientation can no longer be claimed. An incorrectly placed King or Rook also affects castling. Do not carry the main-rule restart table into that regime without checking A.5.1.
Rapid and blitz: timing the claim
In rapid under A.5, and blitz under B.3, an arbiter intervenes on the listed illegal actions, or the opponent claims, before the opponent makes the next move. If neither happens, the illegal move stands. After the reply it cannot be corrected unless the players agree without arbiter intervention. Article A.5.2.
Rapid’s Article A.3 changes the time addition to one minute. Blitz B.2, with one arbiter per game and recording, instead applies Competitive Rules; B.3 imports A.2, A.3 and A.5. The event must announce the applicable regime. A second completed illegal move by the same player is still governed by the loss/draw condition, not another routine minute.
FAQ
Does the first illegal move always lose in blitz?
No. That is not the current general rule. Check B.2 or B.3, the completion of the move and the claim window; Article 7.5.5 distinguishes the first and second offence by the same player.
Can I replace an illegal move with anything I like?
No. After restoration, touch-move and the rules for releasing pieces still apply to the replacement. Ask the arbiter before altering the position.
Is touching an impossible destination already a completed illegal move?
No. Article 7.5.1 identifies pressing the clock as the completion point. Before that, touch-move obligations can still constrain the correction. A teaching board rejecting a click is not a tournament penalty decision.
Related rules
Sources and scope
FIDE Laws of Chess · 2023 · Article 7; A.3–A.6; B.2–B.4.
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.