Attack on the uncastled king: queen to b7 (a6·2)
c9-21818naming tag (square·N)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 1200 ShuffleRating — club-player level.
White to move — find the best continuation
Position on the board
White: king d1, queen a6, rook c1 h1, bishop e1, knight f3, pawn a2 b2 d2 g2 h2 c3.
Black: king d8, queen f4, rook c8 h8, bishop d6 b7, knight a8, pawn c5 a7 e7 g7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 14.
Solution & explanation
Main line
14. Qxb7 Qa4+ 15. Qb3 Qa6 16. Qf7 Nc7 17. Qxg7
Why it works
- Great move! queen to b7 keeps the pressure (+2.1).
- queen to b3 develops smoothly.
- A natural move: queen to f7.
- Best move. queen to g7 is exactly what the engine plays (+2.4).
- You win a piece — the bishop.
- If instead Qa4+, then Qb3 and you win the bishop.
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.
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
About this position
These pieces come from starting position #248.
SP-248 · 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 c1 and h1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 621.
The engine's main line opens with c4.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #248Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-248
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