Attack on the uncastled king: queen to c8 (a6·2)
c9-23764naming 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 3: a forced sequence that ends in checkmate.
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 1760 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 g1, queen a6, rook d1 f1, knight d2 f3, pawn a2 h2 g3 c4 f4 e5 e6.
Black: king e8, queen h3, rook c8 h8, bishop b6 a8, pawn c5 c6 f6 h7.
13 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 3 points of material (32 against 29; 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 24, with 30 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 4. Files fully open (no pawns of either colour): b, d — natural highways for the rooks and queen.
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
24. Qxc8+ Bd8 25. Qd7+ Kf8 26. Qf7#
Why it works
- Great move! queen to c8 keeps the pressure (#2).
- Spot on — queen to d7 (#1).
- Precise: queen to f7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bd8, then Qd7+ and you win the rook.
Move by move
- 24. Qxc8+ — queen to c8 (capture) with check
- Bd8 — bishop to d8
- 25. Qd7+ — queen to d7 with check
- Kf8 — king to f8
- 26. Qf7# — queen to f7 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
About this position
These pieces come from starting position #323.
SP-323 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
The king starts on e1, the rooks on c1 and f1, the queen on d1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 339.
The engine's main line opens with c4.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 49, 400 000 000 nodes).
Explore position #323Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-323
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