Winning blow: king to b1 (a2·6)
c9-21738naming 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 1110 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, queen d8, rook d1 e1, bishop f1 d4, knight e5, pawn b3 h3 a4.
Black: king a7, queen f6, rook c2, bishop g7, knight b7, pawn a5 b6 g6 h7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 7 points of material (31 against 24; 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 a7.
It is White to move on move 29, 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 4. Files fully open (no pawns of either colour): c, d, e, f — natural highways for the rooks and queen. Half-open for White: g.
White hold the bishop pair, an edge in open lines. The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
29. Kb1 Qxd8 30. Kxc2
Why it works
- Great move! king to b1 keeps the pressure (+4.5).
- Well found: king to c2 (+5.0).
- You reach a winning position (+5.0).
- If instead Qxd8, then Kxc2 and you stay on top.
Move by move
- 29. Kb1 — king to b1
- Qxd8 — queen to d8 (capture)
- 30. Kxc2 — king to c2 (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.
King evacuation
The king walks out of the danger zone on its own feet.
King evacuation: when the shelter collapses, the king walks out of the attack on his own feet — sometimes across half the board. A series of precise king moves carries him out of the firing zone, and the enemy attack dissolves. The signs: no direct defense works, but there is a route over unattacked squares to a quiet corner. Calculate the entire journey in advance — a king stranded halfway usually dies there.
About this position
These pieces come from starting position #654.
SP-654 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on c1, the rooks on a1 and d1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionScout family; read right to left it becomes position 212.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 36 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +34 centipawns for White (depth 48, 400 000 000 nodes).
In 50 self-play games White scored 53.0% (95% CI 39.5–66.1%).
Explore position #654Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-654
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