Attack on the uncastled king: pawn to c7 (c6·7)
c9-14106naming 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 2290 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 d2, queen e2, rook a1 h1, bishop g4, knight c2 d3, pawn f2 g2 b3 a4 c4 h5 c6.
Black: king d8, queen h7, rook b8 h8, bishop b2, knight f7 f8, pawn f3 a5 c5 g5 b6 d6 h6.
14 white and 14 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Material is level — 35 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on d2, the black king on d8.
It is White to move on move 25, with 52 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: d.
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
25. c7+ Kxc7 26. Qe7+ Kc6 27. Bxf3+ Qe4 28. Bxe4+
Why it works
- Great move! pawn to c7 keeps the pressure (#4).
- Well found: queen to e7 (#3).
- Precise: bishop to f3 is the top choice (#2).
- Best move. bishop to e4 is exactly what the engine plays (#1).
- You win a piece — the queen.
- If instead Kxc7, then Qe7+ and you stay on top.
Move by move
- 25. c7+ — pawn to c7 with check
- Kxc7 — king to c7 (capture)
- 26. Qe7+ — queen to e7 with check
- Kc6 — king to c6
- 27. Bxf3+ — bishop to f3 (capture) with check
- Qe4 — queen to e4
- 28. Bxe4+ — bishop to e4 (capture) with check
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
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 #170.
SP-170 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on b1 and h1, the queen on g1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneScout family; read right to left it becomes position 789.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #170Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-170
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