Attack on the uncastled king: queen to d7 (d4·4)
c9-23431naming 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 d1, queen d4, rook d3 c4, bishop h3, knight f2, pawn a2 d2 e4 f6.
Black: king d8, queen b6, rook c8 e8, bishop b5 f8, pawn h6 a7 c7 d7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
Material is level — 29 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on d1, the black king on d8.
It is White to move on move 21, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): b, g — natural highways for the rooks and queen. Half-open for White: c, h.
Black hold the bishop pair, an edge in open lines. The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Qxd7+ Bxd7 22. Rxd7#
Why it works
- Great move! queen to d7 keeps the pressure (#1).
- Well found: rook to d7 (#).
- The line ends in a forced mate in 2.
- If instead Bxd7, then Rxd7# and it is mate.
Move by move
- 21. Qxd7+ — queen to d7 (capture) with check
- Bxd7 — bishop to d7 (capture)
- 22. Rxd7# — rook to d7 (capture) and it is checkmate
Types in this puzzle
Epaulette mate
The king's own pieces flank it like epaulettes — mate comes head-on.
In the epaulette mate the king stands between two of its own pieces — most often rooks — like an officer wearing epaulettes. The side squares are blocked by friends, there is no retreat, and the queen mates head-on from directly in front of the king. The sign: a king on the edge rank with both neighboring squares on that rank occupied by its own pieces. Remember, extra defenders crowding the king can be deadlier than no defenders at all.
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 #866.
SP-866 · 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 e1, the queen on b1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 87.
The engine's main line opens with Nf3, bringing the knight out to f3.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #866Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-866
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