Winning blow: king to a3 (b4·2)
c9-27063naming 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 1250 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 b4, queen c4, rook a6, bishop e3, pawn b3 c3 d4.
Black: king d6, queen h2, rook b8, bishop c6, pawn g3 e6.
7 white and 6 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
White are ahead by 1 points of material (20 against 19; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b4, the black king on d6.
It is White to move on move 36, with 4 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 3 pawns, Black 2. Files fully open (no pawns of either colour): a, f, h — natural highways for the rooks and queen. Half-open for White: e, g.
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
36. Ka3 Qh1 37. Bf4+ Ke7 38. Bxb8
Why it works
- Great move! king to a3 keeps the pressure (+6.0).
- Spot on — bishop to f4 (+6.3).
- Strong! bishop to b8 is the sharp choice (+6.6).
- You win a piece — the rook.
- If instead Qh1, then Bf4+ and you stay on top.
Move by move
- 36. Ka3 — king to a3
- Qh1 — queen to h1
- 37. Bf4+ — bishop to f4 with check
- Ke7 — king to e7
- 38. Bxb8 — bishop to b8 (capture)
Types in this puzzle
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
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 #93.
SP-93 · ThroneScout — Centre-file king, rim knight: 204 of the 960 positions share this pattern.
The king starts on e1, the rooks on c1 and f1, the queen on h1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
The second rank carries 2 pawns with no defender at all: a2, b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 872.
The engine's main line opens with f4.
Morozov Balance Index: 11 of 100 — class D — largest edge. Engine evaluation of the starting position: +42 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #93Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-93
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