Attack on the uncastled king: queen to d8 (c7)
c9-27807naming 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.
Mate in 2: the first move creates an unstoppable threat, the second delivers mate.
A fork made possible by the Chess960 piece placement.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1320 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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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.
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 e1, queen c7, rook g1 d5, bishop b1 c1, knight f1, pawn a2 b2 e2 f2 h2 g3 c5 b7.
Black: king e8, queen f6, rook g6 d8, knight d7 f8, pawn g5 a7 e7 f7 h7.
15 white and 11 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
White are ahead by 6 points of material (36 against 30; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e8.
It is White to move on move 13, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 5. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen.
White 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
13. Qxd8+ Kxd8 14. b8=Q#
Why it works
- Great move! queen to d8 keeps the pressure (#1).
- Well found: pawn to b8 (#).
- The line ends in a forced mate in 2.
- If instead Kxd8, then b8=Q# and it is mate.
Move by move
- 13. Qxd8+ — queen to d8 (capture) with check
- Kxd8 — king to d8 (capture)
- 14. b8=Q# — pawn to b8 and it is checkmate
Types in this puzzle
Promotion mate
The pawn promotes — and the new piece mates on the spot.
In a promotion mate the pawn takes its final step and the newborn piece mates on the spot. Sometimes the hero is a knight rather than a queen — it checks from the promotion square in a way no queen can. The sign: the enemy king lingers near the promotion square while your pieces already control its escape routes. When counting pawn races, always check whether the promotion itself is mate — that gains you a full tempo in the evaluation.
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.
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
About this position
These pieces come from starting position #276.
SP-276 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on e1, the rooks on d1 and g1, the queen on h1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on e2, f2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 590.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #276Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-276
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