Attack on the uncastled king: knight to c4 (d2·11)
c9-24761naming 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 1200 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 b1, queen d1, rook g2 a3, bishop f3, knight d2 b7, pawn b2 e2 a4 h4 g5.
Black: king b8, queen e7, rook a8 g8, bishop e5 f7, knight c4, pawn c5 f5 h5 a6 d6 g6.
12 white and 13 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
Black are ahead by 1 points of material (33 against 34; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 22, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c, d, f.
Black hold the bishop pair, an edge in open lines. 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
22. Nxc4 Bxc4 23. Na5 Qe6 24. Nxc4 Qxc4 25. Bd5
Why it works
- Best move. knight to c4 is exactly what the engine plays (+3.9).
- Well found: knight to a5 (+3.8).
- Precise: knight to c4 is the top choice (+4.8).
- Sensible development: bishop to d5.
- You reach a winning position (+5.0).
- If instead Bxc4, then Na5 and you stay on top.
Move by move
- 22. Nxc4 — knight to c4 (capture)
- Bxc4 — bishop to c4 (capture)
- 23. Na5 — knight to a5
- Qe6 — queen to e6
- 24. Nxc4 — knight to c4 (capture)
- Qxc4 — queen to c4 (capture)
- 25. Bd5 — bishop to d5
Types in this puzzle
Bishop fork
The bishop attacks two pieces on crossing diagonals at once.
A bishop fork happens when the bishop lands where two diagonals cross and attacks a target on each of them. Both victims must stand on the bishop's color — that is the first thing to verify. Scan for loose enemy pieces that share the color of squares with their own king or queen. A common sin is placing your own pieces on squares of one color and handing your opponent exactly this geometry.
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #731.
SP-731 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and g1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares 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 pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 417.
The engine's main line opens with a4.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #731Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-731
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