Winning blow: rook to b7 (d7·4)
c9-25801naming 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 1430 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 a2, rook d7, knight a4, pawn c2 d2 e5 a6.
Black: king b8, rook g8, bishop b7, knight e4, pawn g4 c6 e6.
7 white and 7 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
Black are ahead by 2 points of material (12 against 14; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a2, the black king on b8.
It is White to move on move 37, with 26 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): b, f, h — natural highways for the rooks and queen. Half-open for White: g.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. Rxb7+ Kc8 38. Nb6+ Kd8 39. a7 Nc3+ 40. dxc3
Why it works
- Great move! rook to b7 keeps the pressure (#4).
- Spot on — knight to b6 (#3).
- A natural move: pawn to a7.
- Best move. pawn to c3 is exactly what the engine plays (#1).
- You win a piece — the bishop.
- If instead Kc8, then Nb6+ and you win the bishop.
Move by move
- 37. Rxb7+ — rook to b7 (capture) with check
- Kc8 — king to c8
- 38. Nb6+ — knight to b6 with check
- Kd8 — king to d8
- 39. a7 — pawn to a7
- Nc3+ — knight to c3 with check
- 40. dxc3 — pawn to c3 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
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.
Passed pawn
Nothing can stop the passer — escort it to the last rank.
A passed pawn has no enemy pawns in front of it or on the neighboring files: only pieces can stop it. Check who can blockade the pawn or catch it with the king — if nobody can, the pawn is worth a whole piece. Push the passer with your pieces supporting it, and put your rook behind it. The beginner's mistake is shoving the pawn forward unprotected, straight into a capture.
About this position
These pieces come from starting position #946.
SP-946 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on c1, the rooks on b1 and d1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 7.
The engine's main line opens with g3.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #946Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-946
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