Quick answer
Battery is a tactical idea: two aligned attackers on the king file. Work from the first evidence position for Battery, and begin by testing Kg8.
Begin from Kg8 in 5k2/8/R3p3/8/8/2Q5/8/6K1 b - - 1 3. Start with the forcing geometry: checks, captures, threats, defenders and flight squares around the target. The evidence answer is: Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kg8.
In the Battery example, notice: side Black; pieces Black king f8, White rook a6, Black pawn e6, White queen c3, White king g1; legal first moves Kg8, Kf7, Ke7, Ke8, e5. The listed material and candidate moves belong only to this FEN example and should not be generalised.
The tactical trigger
The first evidence board tests two aligned attackers on the king file; the second board tests two aligned attackers on the king file. When a recorded line exists, board A starts from direct FEN setup while board B starts from direct FEN setup. Cross-check wording on the Chess Wiki and on the Tactics hub. Then compare Candidate Moves with X Ray Defense, Windmill, Smothered Mate around the loose unit behind the target.
The two inventories make the distinction concrete. A contains side Black; pieces Black king f8, White rook a6, Black pawn e6, White queen c3, White king g1; legal first moves Kg8, Kf7, Ke7, Ke8, e5; B contains side Black; pieces White queen h8, Black king d7, Black pawn e7, White rook e6, White king g1; legal first moves Kxe6, Kc7. Compare the side to move before comparing the labels in the context of the order of checks before captures.
Topic dossier for this page and board pair r1:5k2 | r2:8 | r3:R3p3 | r4:8 | r5:8 | r6:2Q5 | r7:8 | r8:6K1 / r1:7Q | r2:3kp3 | r3:4R3 | r4:8 | r5:8 | r6:8 | r7:8 | r8:6K1: start with the loose unit behind the target; then test the order of checks before captures; keep the move that closes counterplay separate from a decoy square; use an in-between move before recapture as the transfer check; and reserve a quiet threat after the forcing move for the exception.
Calculation order
On the first board, calculate Kg8 after Kg8 and write down the opponent's best reply around the loose unit behind the target. On the second board, calculate Kxe6 after Kxe6 and check the order of checks before captures. Calculate the most forcing move first, then test the opponent's best capture, interposition or counter-check before naming the motif. In this case the useful condition is a quiet threat after the forcing move.
Key claim: Battery is illustrated here by two aligned attackers on the king file; the first concrete test is Kg8. The board anchor is 5k2/8/R3p3/8/8/2Q5/8/6K1; the example is intentionally narrower than the topic label and should not be generalised without checking the surrounding position..
Practical boundary: To answer “How can a player recognize battery, calculate the winning idea, and test the defender's best resource?”, compare the recorded setup with Kxe6 and the opponent's reply. The decision is useful only when the stated condition survives that concrete test on board 7Q/3kp3/4R3/8/8/8/8/6K1. The evidence records Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position and the second board signature r1:7Q | r2:3kp3 | r3:4R3 | r4:8 | r5:8 | r6:8 | r7:8 | r8:6K1. The false-positive test is whether the move that closes counterplay appears without a decoy square, so the conclusion is useful only when the stated condition survives that concrete test.
Evidence positions
example-1: two aligned attackers on the king file
Show answer
Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kg8.
Why this position is here: Battery is represented by two aligned attackers on the king file. This is a direct FEN setup with board anchor 5k2/8/R3p3/8/8/2Q5/8/6K1; no opening history is inferred from the diagram.
FEN: 5k2/8/R3p3/8/8/2Q5/8/6K1 b - - 1 3
Question: What is the first concrete decision in this battery position?
Answer cue: Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kg8. The first candidate to test is Kg8. Replay Kg8 on board anchor 5k2/8/R3p3/8/8/2Q5/8/6K1 and write down what changes after it.
Evidence boundary: Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position.
example-2: two aligned attackers on the king file
Show answer
Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kxe6.
Why this position is here: Battery is represented by two aligned attackers on the king file. This is a direct FEN setup with board anchor 7Q/3kp3/4R3/8/8/8/8/6K1; no opening history is inferred from the diagram.
FEN: 7Q/3kp3/4R3/8/8/8/8/6K1 b - - 5 3
Question: What is the first concrete decision in this battery position?
Answer cue: Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kxe6. The first candidate to test is Kxe6. Replay Kxe6 on board anchor 7Q/3kp3/4R3/8/8/8/8/6K1 and write down what changes after it.
Evidence boundary: Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position.
example-3: two aligned attackers on the king file
Show answer
Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kd7.
Why this position is here: Battery is represented by two aligned attackers on the king file. This is a direct FEN setup with board anchor 4k3/4p3/5R2/8/5Q2/8/8/6K1; no opening history is inferred from the diagram.
FEN: 4k3/4p3/5R2/8/5Q2/8/8/6K1 b - - 5 3
Question: What is the first concrete decision in this battery position?
Answer cue: Battery: preserve the alignment and calculate the defensive interposition before trading the front piece. Candidate line: Kd7. The first candidate to test is Kd7. Replay Kd7 on board anchor 4k3/4p3/5R2/8/5Q2/8/8/6K1 and write down what changes after it.
Evidence boundary: Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position.
Reading the line
Read the first example (id example-1) as a complete record: continuation Kg8, source fide-laws. This is a direct FEN setup with board anchor 5k2/8/R3p3/8/8/2Q5/8/6K1; no opening history is inferred from the diagram. If A does not expose two aligned attackers on the king file, correct the evidence before relying on the prose.
Read the second example (id example-2) separately: continuation Kxe6, source fide-laws. Its feature is two aligned attackers on the king file; inventory side Black; pieces White queen h8, Black king d7, Black pawn e7, White rook e6, White king g1; legal first moves Kxe6, Kc7. Compare what changes between Kg8 and Kxe6.
The defensive resource
The main mistake to avoid with Battery is spotting a familiar motif but failing to test the defender's strongest legal resource. In A, the missing condition must be located in r1:5k2 | r2:8 | r3:R3p3 | r4:8 | r5:8 | r6:2Q5 | r7:8 | r8:6K1 after Kg8; in B, test it against r1:7Q | r2:3kp3 | r3:4R3 | r4:8 | r5:8 | r6:8 | r7:8 | r8:6K1 after Kxe6.
For Battery, the first board's evidence boundary (after Kg8) is Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position. The second board's evidence boundary for Battery is Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position. If a trusted source or careful calculation changes the conclusion around an in-between move before recapture, update both the evidence record and this article.
Practice from a real game
cover the answer, list checks and captures, and record the defender or escape square that decides whether the idea works. Start with A's side to move and r1:5k2 | r2:8 | r3:R3p3 | r4:8 | r5:8 | r6:2Q5 | r7:8 | r8:6K1; record two candidates, the reply to Kg8 and the correction. Repeat with B's side to move and r1:7Q | r2:3kp3 | r3:4R3 | r4:8 | r5:8 | r6:8 | r7:8 | r8:6K1; the changed board tests transfer rather than diagram memory.
After the drill, compare your notes with X Ray Defense, Windmill, Smothered Mate through a decoy square. Keep A's rejected alternative beside B's chosen line Kxe6; this shows whether the conclusion survived a new board signature.
Sources and scope
Sources for Battery: 1chess.online editorial scope, FIDE Laws of Chess. Source ids are original-analysis, fide-laws. Primary evidence hook: fide-laws. Comparisons and practice notes are editorial. Evidence revision: 2026-08-remediation-r2.
Scope note for board pair r1:5k2 | r2:8 | r3:R3p3 | r4:8 | r5:8 | r6:2Q5 | r7:8 | r8:6K1 / r1:7Q | r2:3kp3 | r3:4R3 | r4:8 | r5:8 | r6:8 | r7:8 | r8:6K1: this page does not claim that Kg8 is an engine principal variation, that an exact endgame result is verified when the evidence says it is not, or that a tool output replaces human calculation. The conclusion is limited to the recorded boundary and the exception the move that closes counterplay.