Learn Chess
What Is Check in Chess? A Complete Rules Guide
If you are new to chess, this guide walks through check in chess, covering the rules around check that every beginner needs. You will learn what check actually means, how the king moves, the castling move that helps protect it, and the situations that trip people up most (checkmate, stalemate, and whether you are ever allowed to put your own king in check). A few practice exercises along the way will help it all stick.
How the King Moves in Chess
The king moves one square at a time, horizontally, vertically, or diagonally. Like the rook, the bishop, the knight, and the queen, the king captures enemy pieces and pawns by landing on their square.
The king is slow. Once it comes under attack, it struggles to reach safety anywhere else on the board. That is exactly why it matters, early in the game, to tuck it away somewhere solid with castling, the special move we get to further down. One more thing before we move on. The king can still pull off real magic in the endgame, as shown in Richard Reti's famous king-and-pawn study.
What Does Check Mean in Chess?
In chess, the king is your life. Lose it, and the game is over. When a king comes under attack, we say it is in check. If you attack your opponent's king, it's common courtesy, especially in casual games, to announce it by simply saying "Check."
The black rook attacks the white king along the back rank. The king is in check. A king is never allowed to move into check or to remain in check.
To get out of check, you can capture the piece giving check, block it by placing a piece between it and your king, or move your king to safety. In this position, the white king can escape the check by moving to h2.
When Check Becomes Checkmate
If a king is in check and has no way out, it is checkmate. Here, the white rook attacks the black king. The black king is in check and cannot escape it. That is checkmate.
White wins the game.
Can You Put Your Own King in Check?
We already said it, but it's worth repeating because beginners ask this all the time. You are never allowed to put your own king in check on purpose. It is against the rules, plain and simple.
Let's look at an example that doubles as your first exercise in this guide. White to play and mate in two.
Your first move is a bit of a surprise (yes, that's a hint). Black will respond, and you finish the game with checkmate.
This is a problem composed by Szasz.
Why bring up this particular puzzle? Because when we first put it to our community, plenty of beginners tried to put their own king in check on the very first move. The most common wrong answer we got was moving the white king to f2. That move is simply illegal. A white king on f2 would stand right next to the black king on g2, which counts as moving into check. It isn't that the move loses the game, it's that you are not allowed to play it at all. A king can never move next to the enemy king, and for that same reason, a king can never capture or directly attack the opposing king.
Did you find the answer? Despite a deceptively simple starting position with very few pieces on the board, this is a genuinely tough exercise. Take your time with it.
The Solution
Here is the solution. The obvious checking moves don't work. If the queen checks the black king outright, the king simply steps aside and there is no mate on the next move. The trick is patience. Play a quiet waiting move so the black king is forced onto a square worse for it than g2.
1.Ke3!!
A king move, of all things, and not an easy one to spot. Moving the king feels completely unnatural when you're hunting for a checkmate, but here it's the key idea. It frees up the f1 square for the black king, and that square turns out to be fatal.
After 1...Kg1 or 1...Kf1, White plays 2.Qf2#, a pattern known as the kiss of death.
The Stalemate Rule in Chess
Here is an important consequence of the rule we just covered. A player can end up with no legal move at all.
Look at the position below, where Black is to move.
Black would love to play something, but simply can't. The black pawns are all stuck, and the black king has no legal square to move to.
When a player is not in checkmate but has no legal moves available, the position is called stalemate, and the game is declared a draw. In the position above, the game is drawn even though White is a whole queen up.
Time for exercise number two. White to play and mate in two.
To solve this one, you need to know that a pawn reaching the far end of the board can promote into any piece of your choice, except a king or another pawn. This is called promotion. Take your time, this one is a clever exercise.
The Solution
Here's the trap. Rushing into 1.f8=Q looks natural, but it's actually stalemate and an immediate draw, despite White's crushing material edge. You need to promote into a different piece instead of the queen. This is called under-promotion, and every once in a while, it really is the best move on the board.
The right move is 1.f8=R!!
Under-promoting to a rook gives the black king a square to run to. After 1...Kh6, it's checkmate with 2.Rh8#.
Don't rush toward the most obvious move.
How Castling Moves the King and Rook Together
The pawn is not the only piece with special moves on the board (en passant, promotion). The king and the rook take part in the only move in chess where two pieces move at the same time, a move called castling. To castle, three conditions must all be true.
- Neither the king nor the rook involved has moved yet.
- The king is not currently in check.
- The king does not cross a square that is under attack while castling.
Once those conditions are met, you move the king two squares toward the rook, and the rook hops to the other side of the king, right next to it. Let's look at an example right away.
White is ready to castle. The knight that stood on g1 has already come out, and so has the bishop, developed diagonally to the light square c4. The space between the white king and the white rook on h1 is now clear.
The king moves two squares toward the rook, and the rook swings to the other side of the king.
And that's castling. Notice that by developing their pieces during the opening, White cleared the way for this move naturally.
Why castle at all? Because it tucks your king away to safety. For the full picture on castling and how it fits into your opening strategy, see our complete guide on how to play chess.
There's also a difference worth knowing. Kingside castling is the short version shown above, and queenside castling is the longer version, when the king heads the other way instead.
Where to Go Next
Check is one of the rules that trips up more beginners than you'd expect, precisely because so much depends on it (how you escape it, when it turns into checkmate, and what happens when neither player can find a legal move at all). Our full guide on how to play chess walks through every rule of the game in about twenty minutes, though getting genuinely good at chess takes a lot longer than that. It's a rich game that calls on a wide range of skills.
A few good next steps from here.
- Read our full breakdown of checkmate, the moment a check becomes unstoppable.
- Get the details on exactly how the king moves, square by square.
- New to the game entirely? Start with our chess basics guide.
- Curious about openings? The Italian Game is one of the most popular ways for White to start a game.
That's our guide to check in chess. We hope it helps one of the game's trickiest rules finally click. If it did, share it with a friend who's learning too.