Attack on the uncastled king: knight to d6 (b5·13)
c9-11418naming 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.
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 1480 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.
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 d1, queen h4, rook c1 f1, bishop h1, knight f3 b5, pawn a2 c2 d2 e2 h2 f4.
Black: king d8, queen e8, rook c7 f8, bishop a8 h8, knight h5 c6, pawn f5 g6 a7 b7 d7 e7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Black are ahead by 3 points of material (34 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 d1, the black king on d8.
It is White to move on move 11, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: b, g.
Black hold the bishop pair, an edge in open lines. The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
11. Nd6 Bf6 12. Nxe8 Bxh4 13. Nxc7
Why it works
- Great move! knight to d6 keeps the pressure (+2.8).
- A brilliant blow: knight to e8, and you stand better (+2.8).
- Stunning! knight to c7 gives up material but you stand better (+2.8).
- You win a piece — the queen.
- If instead Bf6, then Nxe8 and you win the queen.
Move by move
- 11. Nd6 — knight to d6
- Bf6 — bishop to f6
- 12. Nxe8 — knight to e8 (capture)
- Bxh4 — bishop to h4 (capture)
- 13. Nxc7 — knight to c7 (capture)
Types in this puzzle
Queen trap
The strongest piece ventures too far — and cannot come back.
A queen trap catches the strongest piece after it ventures too far and finds no way home. The usual story is a queen grabbing a distant pawn — the classic poisoned pawn. The warning signs: the queen has few retreat squares, and enemy minor pieces cut them off one by one, gaining tempo with every move. Before your queen snacks on a pawn in enemy territory, count her escape routes — fewer than two means stay home.
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.
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.
About this position
These pieces come from starting position #339.
SP-339 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on c1 and f1, the queen on e1.
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.
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 323.
The engine's main line opens with g4.
Morozov Balance Index: 89 of 100 — class A — most balanced. Engine evaluation of the starting position: +14 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #339Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-339
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