Winning blow: king to b2 (b3)
c9-25588naming 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 1390 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 b3, queen f3, rook f1 b4, pawn d2 h2 g3 b6 c6 c7.
Black: king c8, queen f7, rook d6 a8, knight f6, pawn d4 e5 h5 g7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
Black are ahead by 1 points of material (25 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b3, the black king on c8.
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 6 pawns, Black 4. Files fully open (no pawns of either colour): a, f — natural highways for the rooks and queen. Half-open for White: e.
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. Kb2 Qa2+ 37. Kc1 Re6 38. b7+ Kxc7 39. bxa8=R
Why it works
- Great move! king to b2 keeps the pressure (+3.6).
- king to c1 develops smoothly.
- Precise: pawn to b7 is the top choice (+4.5).
- Best move. pawn to a8 is exactly what the engine plays (+4.7).
- You win a piece — the rook.
- If instead Qa2+, then Kc1 and you stay on top.
Move by move
- 36. Kb2 — king to b2
- Qa2+ — queen to a2 with check
- 37. Kc1 — king to c1
- Re6 — rook to e6
- 38. b7+ — pawn to b7 with check
- Kxc7 — king to c7 (capture)
- 39. bxa8=R — pawn to a8 (capture)
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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.
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 #929.
SP-929 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on c1, the rooks on b1 and e1, the queen on g1.
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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 27.
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 47, 400 000 000 nodes).
Explore position #929Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-929
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