Attack on the uncastled king: queen to b7 (h1·10)
c9-09822naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 h1, rook d1 f1, bishop d2 e2, knight e3, pawn a2 f2 c3 g3 h4.
Black: king e8, queen e5, rook a8 g8, bishop b7 e7, knight a7 f8, pawn a5 h5 b6 e6 g6 c7.
12 white and 14 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 4 points of material (33 against 37; 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 e8.
It is White to move on move 17, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: b, e.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
17. Qxb7 Rd8 18. Qxa7
Why it works
- Great move! queen to b7 keeps the pressure (+4.1).
- Spot on — queen to a7 (+4.1).
- You win a piece — the bishop.
- If instead Rd8, then Qxa7 and you win the bishop.
Move by move
- 17. Qxb7 — queen to b7 (capture)
- Rd8 — rook to d8
- 18. Qxa7 — queen to a7 (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.
Trapped piece
The attacked piece has no safe square — it is caught.
Trapping a piece means the attacked piece has no safe square left — it simply perishes. Do not chase it around; build a cage instead: cut off the escape squares with pawns and pieces first, and attack last. The typical victim has wandered deep into your camp or is stuck at the edge of the board, where its mobility is tiny. And always check the way home for your own raiders — or the trapped piece will be yours.
About this position
These pieces come from starting position #565.
SP-565 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on e1, the rooks on a1 and g1, the queen on h1.
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 c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
The pawn on f2 is defended by the king alone — the classic soft spot of the standard setup.
The setup belongs to the ThroneGuard family; read right to left it becomes position 490.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 6 of 100 — class D — largest edge. Engine evaluation of the starting position: +60 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 52.0% (95% CI 38.5–65.2%).
Explore position #565Provenance
Mined from the project's engine self-play games.
Pack 004 · SP-565
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