Attack on the uncastled king: knight to e6 (d4·24)
c9-25706naming 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 1290 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 g1, queen d2, rook b1 f1, bishop b2, knight d4, pawn a2 b3 e3 g3 c4 g4.
Black: king d8, queen c7, rook c8 g8, knight e5 d6, pawn b6 e6 h6 a7 d7 f7 g7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 1 points of material (31 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 g1, the black king on d8.
It is White to move on move 17, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d, f, h.
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
17. Nxe6+ dxe6 18. Bxe5 O-O 19. Qxd6
Why it works
- Great move! knight to e6 keeps the pressure (+4.1).
- Well found: bishop to e5 (+3.9).
- Precise: queen to d6 is the top choice (+4.0).
- You win a piece — the knight.
- If instead dxe6, then Bxe5 and you stay on top.
Move by move
- 17. Nxe6+ — knight to e6 (capture) with check
- dxe6 — pawn to e6 (capture)
- 18. Bxe5 — bishop to e5 (capture)
- O-O — king to g8
- 19. Qxd6 — queen to d6 (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.
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
About this position
These pieces come from starting position #786.
SP-786 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on b1 and g1, the queen on c1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
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 ThroneScout family; read right to left it becomes position 167.
The engine's main line opens with c4.
Morozov Balance Index: 97 of 100 — class A — most balanced. Engine evaluation of the starting position: +2 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 53.0% (95% CI 39.5–66.1%).
Explore position #786Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-786
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