Winning blow: rook to e1 (a1·6)
c9-26496naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1200 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king g2, queen c5, rook a1, bishop c2, knight f2, pawn a2 b2 c3 f3 g3 f4 h4.
Black: king d8, queen b8, rook e1 a8, bishop c7, knight f6, pawn b5 d5 h5 a7 f7 g7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
Black are ahead by 4 points of material (27 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g2, the black king on d8.
It is White to move on move 23, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: d.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
23. Rxe1 Bd6 24. Qc6 a6 25. Bb3 Ra7 26. Bxd5
Why it works
- Great move! rook to e1 keeps the pressure (+3.8).
- queen to c6 develops smoothly.
- A natural move: bishop to b3.
- Best move. bishop to d5 is exactly what the engine plays (+3.4).
- You win a piece — the rook.
- If instead Bd6, then Qc6 and you win the rook.
Move by move
- 23. Rxe1 — rook to e1 (capture)
- Bd6 — bishop to d6
- 24. Qc6 — queen to c6
- a6 — pawn to a6
- 25. Bb3 — bishop to b3
- Ra7 — rook to a7
- 26. Bxd5 — bishop to d5 (capture)
Types in this puzzle
X-ray
A long-range piece acts through an enemy piece on the same line.
An X-ray lets a long-range piece act through an enemy piece standing on the same line — its power shines straight through. The square behind looks safe or defended, and that illusion is exactly what the tactic exploits. Check your rooks, bishops and queens: is a key square or a target hiding behind an enemy piece on their line? When counting captures on a square, include the X-ray attackers — they join the fight the moment the line opens.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
About this position
These pieces come from starting position #413.
SP-413 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on f1, the rooks on a1 and h1, the queen on b1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 744.
The engine's main line opens with c3.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #413Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-413
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