Attack on the uncastled king: knight to d4 (c2·3)
c9-14372naming 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.
A fork made possible by the Chess960 piece placement.
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 1110 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.
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.
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 c1, queen d2, rook b1 f1, bishop a5, knight c2 e5, pawn e2 f2 h2 g3 b4.
Black: king d8, queen b5, rook b8 f8, bishop c6 h8, knight h6 c7, pawn a6 d6 e7 f7 g7 h7.
12 white and 14 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Black are ahead by 4 points of material (33 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 c1, the black king on d8.
It is White to move on move 18, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen. Half-open for White: a, d.
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
18. Nd4 Ke8 19. Nxb5
Why it works
- Great move! knight to d4 keeps the pressure (+2.6).
- Spot on — knight to b5 (+3.6).
- You win a piece — the queen.
- If instead Ke8, then Nxb5 and you win the queen.
Move by move
- 18. Nd4 — knight to d4
- Ke8 — king to e8
- 19. Nxb5 — knight to b5 (capture)
Types in this puzzle
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.
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.
Knight fork
One knight move attacks two targets at once — the opponent can only save one.
A fork is one move that attacks two targets at once, and no piece forks better than the knight. Look through the knight's eyes: it jumps in an L and never moves along straight lines, which is exactly why its threats get missed. Both victims of a knight fork always stand on squares of one color, while the knight strikes from the opposite color. Hunt for the square from which the knight hits the king and a heavy piece at once.
About this position
These pieces come from starting position #343.
SP-343 · ThroneScout — A central king (d or e), but with a knight posted out on the a- or h-file.
The king starts on d1, the rooks on b1 and f1, the queen on e1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 322.
The engine's main line opens with d3.
Morozov Balance Index: 93 of 100 — class A — most balanced. Engine evaluation of the starting position: +11 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #343Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-343
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