Battery in chess

A battery is two pieces lined up on the same line so they attack together: a queen and bishop on a diagonal, or two rooks (or a queen and rook) on a file. The front piece can capture or give check with the back piece supporting it.

• Doubled rooks on an open file, or a queen in front of a bishop, aimed at the enemy king's pawns.
• Count attackers and defenders on the target square: a battery adds one attacker without needing another route.
• Classic target: h7 (h2 for Black) with queen and bishop.

Solution: 1.Qxh7#. Qxh7#. The king can't take the queen because the b1 bishop protects h7. Batteries double your firepower on one square.

Solution: 1.Rd8+ Rxd8 2.Rxd8#. Rd8+! Rxd8 Rxd8#. The rooks were doubled (a 'battery'), so when the first one is taken, the second one lands on d8 with mate. Doubling rooks on an open file is one of the strongest ways rooks can work together.

Wingo, our coach, never works out chess moves on its own. Stockfish finds the best line, chess.js writes down the facts of the position, and Wingo's explanation is built from that analysis. This is its real answer for "Queen + Bishop Battery", unedited (a person checked it before it went on this page).

Side to move: White.
White: king g1, queen d3, bishop b1, pawn f2, pawn g2, pawn h2.
Black: king g8, rook f8, pawn f7, pawn g7, pawn h7.
Material: White 15, Black 8 (White up 7).
King in check (verified):
After 1.Qxh7#: Black king on g8 is in check from the White queen on h7. Squares next to the king: f7: blocked by its own pawn; f8: blocked by its own rook; g7: blocked by its own pawn; h7: covered by White bishop b1 (the White queen there is protected); h8: covered by White queen h7; the other squares are off the board (edge). King moves: none. Capture the checking piece with another piece: impossible. Block the check: impossible. This is checkmate.
Loose/under-defended pieces: none.
Defenders and attackers (verified):
Black rook f8: defended by king g8; attacked by nothing.
White queen d3: defended by bishop b1; attacked by nothing.
White bishop b1: defended by queen d3; attacked by nothing.
Line-ups (verified geometry): Black rook f8 and Black king g8 are on the 8th rank (nothing between them); White bishop b1 and White king g1 are on the 1st rank (nothing between them).
White's legal moves (34): queen d3: Qc4, Qb5, Qa6, Qd4, Qd5, Qd6, Qd7, Qd8, Qe4, Qf5, Qg6, Qxh7#, Qe3, Qf3, Qg3, Qh3, Qe2, Qf1, Qd2, Qd1, Qc2, Qc3, Qb3, Qa3; pawn f2: f3, f4; pawn g2: g3, g4; pawn h2: h3, h4; bishop b1: Ba2, Bc2; king g1: Kh1, Kf1.
Engine best line: 1.Qxh7# — forced mate in 1 for White.
Best move theme: checkmate.

Our mistake finder checks your recent games with Stockfish and lists the 3 mistakes you repeat most. Missed batterys are counted under "Missing forks and double attacks". Every mistake it finds becomes a puzzle from your own game, so you practise exactly the positions you got wrong.

Puzzles tell you a battery is there. In a game nobody does. Play Blaze, one of our bots that think at a human pace and make human mistakes, and look for the pattern yourself. The coach can point it out afterwards if you miss it.