Attack on the uncastled king: knight to d6 (e4·14)
sf-u-0229naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Mate in 2: the first move creates an unstoppable threat, the second delivers mate.
Chess960 twist: use the unusual starting setup of the pieces.
Difficulty 1090 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
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.
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.
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.
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 f1, queen g5, rook d1 e2, bishop a1, knight f3 e4, pawn a2 f2 g2 h2 b3 d3 c4.
Black: king e8, queen b7, rook d8 h8, bishop a8, knight h5, pawn b5 c5 a6 e6 h6 d7 g7.
14 white and 13 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 3 points of material (35 against 32; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on e8.
It is White to move on move 17, with 56 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: e.
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
17. Nd6+ Kf8 18. Qxd8#
Why it works
- Great move! knight to d6 keeps the pressure (#1).
- Spot on — queen to d8 (#).
- The line ends in a forced mate in 2.
- If instead Kf8, then Qxd8# and it is mate.
Move by move
- 17. Nd6+ — knight to d6 with check
- Kf8 — king to f8
- 18. Qxd8# — queen to d8 (capture) and it is checkmate
Types in this puzzle
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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 007
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