Double check: the most forcing move in chess
Nothing else in chess narrows a position this far. Whatever the opponent's position, in a double check they have exactly one kind of legal reply.
- 120 positions in the course
- Difficulty 500–2264
- Section: Sharper Tactics
- 5 levels
What a double check is
A double check is a discovered check where the piece that moves also gives check. Two pieces are attacking the king simultaneously, and since one move can only capture one attacker or block one line, the king must move.
That makes it the single most forcing move available in chess. It works regardless of material -- the checking pieces can both be hanging and it does not matter, because there is no legal move that takes either of them.
How to spot it
- Look for a piece standing in front of a rook, bishop or queen that already points at the enemy king.
- Then find a square for that front piece from which it also gives check.
- Knights are the classic front piece, because a knight can check from a square no line piece could occupy.
- Once you have a double check, calculate only king moves. There is nothing else to check.
Three double checks
Three positions from the 120 in this skill, easiest first. The highlighted squares are the move your opponent has just played. Work it out before you open the answer.
Position 1
Black to move. Find the best move.
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22.b4 22...Ne2#
The line ends in checkmate. Both checks cannot be answered by one move, so the king has to move and everything else on the board is irrelevant for a turn.
The position comes from the middlegame of a real game, rated 815 for difficulty. The answer reaches checkmate.
Position 2
Black to move. Find the best move.
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26.Kh2 26...Nf1+ 27.Kg1 27...Qh2#
The line ends in checkmate. Both checks cannot be answered by one move, so the king has to move and everything else on the board is irrelevant for a turn.
The position comes from an endgame of a real game, rated 1345 for difficulty. The answer reaches checkmate.
Position 3
White to move. Find the best move.
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21...Rxf3 22.hxg6 Rxe3 23.gxf7+
The line comes out 1 pawn ahead. Both checks cannot be answered by one move, so the king has to move and everything else on the board is irrelevant for a turn.
The position comes from an endgame of a real game, rated 1894 for difficulty. The answer reaches a winning advantage.
The defensive lesson
There is no defence to a double check except a king move, so the defensive work happens earlier: do not allow a position where an enemy piece sits on a line between its own long-range piece and your king.
In practice most double checks arrive after the king has already been dragged onto an open file or diagonal by an earlier sacrifice, so the real warning sign is the sacrifice, not the check.
Questions people ask
What is a double check in chess?
A check given by two pieces at the same time, produced when a piece moves to give check and simultaneously uncovers a check from a piece behind it. The king must move; nothing can be captured or blocked.
Can you block a double check?
No. Blocking stops one line, and the other check remains. The same is true of capturing -- you can only take one of the two checking pieces. The king has to move.
Is double check stronger than checkmate?
It is more forcing than any other non-mating move, but it is not mate. If the king has a legal square it survives. Its value is that it wins an entire tempo unconditionally, which is often enough to mate next move.
Nearby patterns
Double Check sits in Sharper Tactics. The rest of that section:
- Discovered AttacksMove one piece, attack with another
- DeflectionDrag the defender away
- AttractionLure a piece to a bad square
- X-RayAttacking through a piece
- ClearanceGet out of your own way
Tell it apart from its neighbour
Double Check is confused with these more often than anything else, and the difference is usually one sentence long.
Printable worksheetsThree free PDF sheets of these positions with a full answer key. No sign-up, print and copy as many as you like.