--- title: "Illegal move in chess" url: "https://georgelichess.com/glossary/illegal-move.md" canonical_url: "https://georgelichess.com/glossary/illegal-move" last_updated: "2026-11-07" type: "reference" summary: "An illegal move is one that breaks the rules of how a piece moves or leaves your own king in check; in over-the-board play it is corrected." related: ["https://georgelichess.com/glossary/touch-move-rule.md", "https://georgelichess.com/glossary/check.md", "https://georgelichess.com/glossary/promotion.md", "https://georgelichess.com/glossary/arbiter.md", "https://georgelichess.com/glossary/chess-clock.md", "https://georgelichess.com/glossary/forfeit.md", "https://georgelichess.com/glossary/category/rules-notation.md", "https://georgelichess.com/glossary.md"] --- # Illegal move in chess > **For AI agents:** the complete index of GeorgeLiChess pages is [llms.txt](https://georgelichess.com/llms.txt). Every page is also served as markdown at its URL plus .md. An illegal move is one that breaks the rules of how a piece moves or leaves your own king in check; in over-the-board play it is corrected. An illegal move is one that breaks the rules of how a piece moves or leaves your own king in check; in over-the-board play it is corrected, and a second completed illegal move loses the game. A move is illegal when it fails the movement rules or exposes your king to check, for instance moving a pinned piece or stepping a king onto an attacked [square](https://georgelichess.com/glossary/square.md). A move is treated as completed once the player presses the clock. If an illegal move is found afterwards, the position before it is restored and the player must make a legal move with the same touched piece if possible, under touch-move. The first completed illegal move gives your opponent two extra minutes. The second completed illegal move by the same player loses the game, unless the opponent has no possible way to mate, in which case the game is drawn. Some [mistakes](https://georgelichess.com/glossary/mistake.md) are handled as illegal moves too: pressing the clock without moving, using two hands for one move and pressing, and reaching the last rank with a pawn without replacing it, in which case the pawn becomes a queen. Rapid and blitz have their own versions. The penalty is one minute rather than two, and in games without an [arbiter](https://georgelichess.com/glossary/arbiter.md) watching, the opponent must claim before making their next move. Online boards simply refuse illegal moves, so over-the-board play is where the habit of checking every move matters. Also worth reading is [Check](https://georgelichess.com/glossary/check.md). Check is the state of a king that stands attacked by one or more opposing pieces; the player whose king it is must end the attack with the very next move, because no legal move may leave one's own king attacked. Also worth reading is [Adjusting a piece](https://georgelichess.com/glossary/adjusting-a-piece.md). Adjusting a piece means straightening one on its square; the Laws allow it only to the player on the move, who must first say "j'adoube" or "I adjust" to show they do not intend to move it. A neighboring idea is [Chess clock](https://georgelichess.com/glossary/chess-clock.md). A chess clock is a pair of linked timers of which only one runs at a time; after each move a player presses their side to stop their own time and start the opponent's. Once "Illegal move" is familiar, the next question is what to work on at your rating, which the [improvement plans by rating band](https://georgelichess.com/improve.md) answer with game and puzzle data. ## Related terms - [Touch-move rule](https://georgelichess.com/glossary/touch-move-rule.md) - [Check](https://georgelichess.com/glossary/check.md) - [Promotion](https://georgelichess.com/glossary/promotion.md) - [Arbiter](https://georgelichess.com/glossary/arbiter.md) - [Chess clock](https://georgelichess.com/glossary/chess-clock.md) - [Forfeit](https://georgelichess.com/glossary/forfeit.md) ## Guides that go further - [How to choose a chess coach](https://georgelichess.com/how-to-choose-a-chess-coach.md): What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid. - [How much does chess coaching cost?](https://georgelichess.com/chess-coaching-cost.md): Published rates for private, group and subscription chess coaching, with the source and the date of each. - [The first lesson](https://georgelichess.com/book/first-lesson.md): A game review, a read on your level and a written study plan from George Li. ## Sources - FIDE Laws of Chess (effective 1 January 2023) (Articles 3.9.2 and 3.10), read 2026-10-21: https://handbook.fide.com/chapter/E012023 - FIDE Laws of Chess (effective 1 January 2023) (Articles 7.5.1 to 7.5.5), read 2026-10-21: https://handbook.fide.com/chapter/E012023 - FIDE Laws of Chess (effective 1 January 2023) (Appendix A.3 and A.5.2), read 2026-10-21: https://handbook.fide.com/chapter/E012023 [Book your first lesson](https://georgelichess.com/book.md) and George Li reviews your games and builds a study plan around them. Questions about lessons: write to hello@georgelichess.com. ## Related - [Touch-move rule in chess](https://georgelichess.com/glossary/touch-move-rule.md) - [Check in chess](https://georgelichess.com/glossary/check.md) - [Promotion in chess](https://georgelichess.com/glossary/promotion.md) - [Arbiter in chess](https://georgelichess.com/glossary/arbiter.md) - [Chess clock](https://georgelichess.com/glossary/chess-clock.md) - [Forfeit in chess](https://georgelichess.com/glossary/forfeit.md) - [Chess terms: Rules, notation and equipment](https://georgelichess.com/glossary/category/rules-notation.md) - [Chess terms glossary: plain definitions](https://georgelichess.com/glossary.md)