Attack on the uncastled king: queen to f7 (f5·4)
c9-27790naming 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 1290 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.
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 g1, queen f5, rook e1 f1, bishop b1, knight e4 d7, pawn a2 e2 g2 h2 d4.
Black: king g8, queen a3, rook h6 e8, bishop b8 c8, knight b7 c7, pawn h4 c6 a7 g7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 2 points of material (33 against 35; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 17, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): b, f — natural highways for the rooks and queen. Half-open for White: c.
Black hold the bishop pair, an edge in open lines. 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
17. Qf7+ Kh8 18. Nxb8 h3 19. Qxc7
Why it works
- Great move! queen to f7 keeps the pressure (+2.8).
- Spot on — knight to b8 (+3.1).
- Precise: queen to c7 is the top choice (+3.6).
- You win a piece — the bishop.
- If instead Kh8, then Nxb8 and you win the bishop.
Move by move
- 17. Qf7+ — queen to f7 with check
- Kh8 — king to h8
- 18. Nxb8 — knight to b8 (capture)
- h3 — pawn to h3
- 19. Qxc7 — queen to c7 (capture)
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.
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.
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
About this position
These pieces come from starting position #52.
SP-52 · RampartScout — A knight in the corner and the king out on the wing (b/g); like every family, it is closed under mirror twins.
The king starts on g1, the rooks on e1 and h1, the queen on f1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the RampartScout family; read right to left it becomes position 910.
The engine's main line opens with f4.
Morozov Balance Index: 62 of 100 — class B — balanced. Engine evaluation of the starting position: +18 centipawns for White (depth 49, 400 000 000 nodes).
In 50 self-play games White scored 55.0% (95% CI 41.3–67.9%).
Explore position #52Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-52
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