Double check in chess
Two checks at the same time. The king has to move - there is no other legal answer.
Play through Reti-Tartakower → Vienna, 1910 — the queen sacrifice and the double check that follows it.
A double check is a discovered check where the moving piece also gives check, so two pieces attack the king simultaneously.
Why the king must move
There are only three legal answers to a check: capture the checking piece, block the line, or move the king. Against a double check, capturing removes only one checker and blocking stops only one line. Only the king move can deal with both.
That has a consequence worth memorising: in a double check, material does not matter. Your checking pieces can both be hanging. The opponent has no time to take them.
Because the king is forced to move, double check is the engine behind smothered mate, back-rank breakthroughs and most queen sacrifices that end in mate.
How to create one
- Line up a bishop, rook or queen on the enemy king's file, rank or diagonal with one of your own pieces in between.
- Find a move for the in-between piece that also gives check - a knight jump is the classic, since a knight can check from squares no line piece covers.
- Do not worry whether the moving piece is defended.
The famous example
Reti-Tartakower, Vienna 1910. After 1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nf6 5.Qd3 e5 6.dxe5 Qa5+ 7.Bd2 Qxe5 8.O-O-O Nxe4, White played 9.Qd8+!! - and after the forced 9...Kxd8, 10.Bg5+ is a double check. The king cannot capture, cannot block, and both retreats are mate: 10...Kc7 11.Bd8# and 10...Ke8 11.Rd8#.
The queen sacrifice only works because the follow-up is a double check. With any single check, Black would have time to deal with it and remain a queen up.
Practise the double check
Reading about a pattern is not the same as seeing it under time pressure. The puzzle trainer serves rated positions taken from real games, adjusting to your level as you solve - and any puzzle you get wrong opens on the full analysis board in one click, so you can find out exactly what you missed.
Related tactics
Discovered attack
Move one piece and a completely different piece delivers the threat. Two attacks for the price of one move.
Smothered mate
The prettiest mate in chess: the king is trapped by its own defenders, and a knight delivers the blow.
Back rank mate
A castled king behind three untouched pawns has no escape squares. A rook or queen on the back rank ends the game.
Frequently asked questions
Can you block a double check?
No. Blocking stops one line, and the other checking piece still attacks the king. The king must move.
Can you capture a piece giving double check?
Only if the capture somehow answers both checks, which is effectively impossible. Capturing one checker leaves the other one still checking, so the move is illegal.