Winning blow: king to c4 (b3·2)
c9-23660naming 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 b3, queen a3, rook b6, knight b5, pawn g2 c3 f3 b7.
Black: king b8, queen b1, rook e2, bishop h8, pawn d3 f4 d6.
8 white and 7 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 1 points of material (21 against 20; 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 b8.
It is White to move on move 37, with 3 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 4 pawns, Black 3. Files fully open (no pawns of either colour): a, e, h — 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
37. Kc4 Qa2+ 38. Qxa2 Rxa2 39. Kxd3
Why it works
- Great move! king to c4 keeps the pressure (+4.0).
- Well found: queen to a2 (+4.2).
- Precise: king to d3 is the top choice (+4.3).
- You reach a winning position (+4.3).
- If instead Qa2+, then Qxa2 and you win the queen.
Move by move
- 37. Kc4 — king to c4
- Qa2+ — queen to a2 with check
- 38. Qxa2 — queen to a2 (capture)
- Rxa2 — rook to a2 (capture)
- 39. Kxd3 — king to d3 (capture)
Types in this puzzle
Overload
One defender guards two things — it cannot do both jobs.
Overloading exploits a defender with two jobs at once — guarding a piece and covering a mating square, for instance. It cannot do both: your first strike forces it to handle one duty and abandon the other. Find the overworked piece by asking what happens to each of its charges if it gets distracted. Then hit one target and collect the other — an overloaded defender only pretends to defend.
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 #750.
SP-750 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on b1, the rooks on a1 and h1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
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 c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 404.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #750Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-750
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