Attack on the uncastled king: knight to c6 (e5·8)
c9-10880naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 d1, rook b1 h1, bishop a1 f1, knight e5, pawn a2 g2 f3 c4 e4 h4.
Black: king g8, queen d8, rook h6 b8, bishop c6 f8, knight d6 e8, pawn b4 h5 b6 c7 f7 g7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 13.
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 g1, the black king on g8.
It is White to move on move 13, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: b.
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
13. Nxc6 Qc8 14. Nxb8
Why it works
- Great move! knight to c6 keeps the pressure (+2.2).
- A brilliant blow: knight to b8, and you stand better (+1.9).
- You win a piece — the rook.
- If instead Qc8, then Nxb8 and you win the rook.
Move by move
- 13. Nxc6 — knight to c6 (capture)
- Qc8 — queen to c8
- 14. Nxb8 — knight to b8 (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 #418.
SP-418 · RampartGuard — Both knights begin on inner files while the king sits on the wing (b/g); mirror twins stay together in this family.
The king starts on g1, the rooks on b1 and h1, the queen on d1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on f2 is defended by the king alone — the classic soft spot of the standard setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 727.
The engine's main line opens with c4.
Morozov Balance Index: 100 of 100 — class A — most balanced. Engine evaluation of the starting position: -2 centipawns for White (depth 47, 400 000 000 nodes).
In 50 self-play games White scored 51.0% (95% CI 37.6–64.3%).
Explore position #418Provenance
Mined from the project's engine self-play games.
Pack 004 · SP-418
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