ChessA double check is two pieces giving check to the enemy king at the same time. When you're in double check, you can't block it and you can't capture both pieces. The only way out is to move the king. It's the strongest check in chess, and when you play free chess online, one double check often decides the whole game.
What it looks like
Almost every double check is made the same way. One piece stands on the line of a rook, bishop or queen. When it jumps away, it gives check itself and opens the line behind it at the same time.
Normally there are three ways out of check: move the king, block, or capture the checking piece. Here two pieces are giving check. The black queen on c7 can take the knight on d6, but then the rook is still giving check. Block the rook on the e-file, and the knight is still giving check. One move can only fix one problem, so the king has to move.
Two ways to use a double check
Win material
Your opponent can only move the king, so it's like you get a free move. Use it to grab something, and your opponent can't protect it.
Checkmate
If the king has no free squares around it, a double check is simply checkmate, because there's no chance to block or capture.
A real example: a classic mate from over a hundred years ago
There's a famous old game that started as a Caro-Kann Defense. White gives the queen away to the black king, then finishes with a double check:
Black is a queen up but can't save the king. A double check forces a king move, so the black king gets pushed every move until there's nowhere left to run. The key to this mate is the white rook on the d-file after queenside castling (see the Caro-Kann Defense for more on this opening).
How to defend
- Watch out for enemy pieces standing "in the way" in front of your king. If only one enemy piece stands between your king and an enemy rook, bishop or queen, the moment it moves it's a discovered check, and it may well be a double check.
- Leave your king room to run. In a double check only the king can move, so if all the squares around it are blocked, it's mate.
- Castle early. A king left on the central e-file is the easiest target for a rook-and-knight double check.
Practice puzzles
Show answer
1. Bg5# The bishop goes to g5. The bishop gives check on the diagonal, and the rook on d1 gives check down the open d-file. That's a double check. e7 is covered by the bishop, d7 by the rook, and c8, e8 and c7 hold Black's own pieces. Checkmate.
Show answer
1. Ng6+ The knight jumps to g6. The knight gives check and so does the bishop on b2: double check. The h7 pawn can't take the knight, so the king has to go to g8, and next move the knight takes the queen on h4.
Show answer
1. Nf6# The knight goes to f6. The knight and rook both give check, so the king has to move. But e7 is covered by the rook, d7 by the knight on f6, and every other square holds a black piece. Checkmate. After Nd6, the king could still escape to d7.
FAQ
Why do you have to move the king in a double check?
There are only three ways out of check: move the king, block, or capture the checking piece. With two pieces giving check, blocking one line or capturing one piece leaves the other still giving check. Only a king move works.
How is a double check related to a discovered check?
A discovered check is when one piece moves away and the piece behind it gives check. If the piece that moved also happens to give check, it becomes a double check. So almost every double check grows out of a discovered check.
Can three pieces give check at once?
Not in a normal game. One move can make at most two pieces give check: the piece that moved, and the one whose line it opened.
Try it yourself
A double check is a souped-up discovered attack, and it's worth looking at alongside the fork. More tactics are in chess tactics. The next time you play chess against the computer, notice whether your knight or bishop is standing in front of your own rook or queen. That's a double-check chance.