Attack on the uncastled king: knight to d5 (b4·2)
c9-06885naming 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 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.
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 c1, rook a1 h3, bishop e3, knight g3 b4, pawn e2 f2 g2 a3 d4 h4 c5.
Black: king g8, queen c7, rook e8 h8, bishop a5 d5, knight e6 d7, pawn c3 h5 g6 a7 e7 f7.
14 white and 14 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 2 points of material (35 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 16, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen.
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
16. Nxd5 Qb7 17. Nxc3
Why it works
- Great move! knight to d5 keeps the pressure (+1.7).
- Spot on — knight to c3 (+1.6).
- You win a piece — the bishop.
- If instead Qb7, then Nxc3 and you win the bishop.
Move by move
- 16. Nxd5 — knight to d5 (capture)
- Qb7 — queen to b7
- 17. Nxc3 — knight to c3 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
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 #405.
SP-405 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on g1, the rooks on a1 and h1, the queen on b1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
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 746.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #405Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 004 · SP-405
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