Attack on the uncastled king: queen to c6 (d7)
c9-05576naming 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.
A fork made possible by the Chess960 piece placement.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 2060 ShuffleRating — expert level — few solve it at first try.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
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 b1, queen d7, rook a1 c1, bishop e1 f3, knight f2, pawn b2 g2 h2 e3 c4 d4 a6.
Black: king b8, rook a8 c8, bishop g5 g6, knight g1, pawn f5 b6 a7 c7 g7 h7.
14 white and 12 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
White are ahead by 10 points of material (35 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 16, with 51 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: f.
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
16. Qc6 f4+ 17. Ka2 Bb1+ 18. Raxb1
Why it works
- Great move! queen to c6 keeps the pressure (#3).
- king to a2 develops smoothly.
- Precise: rook to b1 is the top choice (#1).
- You win a piece — the bishop.
- If instead f4+, then Ka2 and you stay on top.
Move by move
- 16. Qc6 — queen to c6
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Battery
Two pieces stacked on one line — the front one strikes with double force.
A battery stacks two long-range pieces on one line — a queen behind a bishop on a diagonal, or doubled rooks on a file. The front piece strikes with double force: capture it, and the piece behind recaptures with even more pressure. The battery is ready when both pieces already stare at one point and only the front strike is missing. Build batteries in advance on lines leading to the king — the doubling itself often breeds the combination.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #937.
SP-937 · RampartScout — A wing-file king (b or g) and at least one corner knight: the rarest of the six families, just 72 positions.
The king starts on b1, the rooks on a1 and c1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 25.
The engine's main line opens with a4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #937Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 014 · SP-937
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