Attack on the uncastled king: pawn to d3 (c2·20)
c9-24467naming 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 f1, queen h2, rook e1 g1, bishop h5, knight c3, pawn a2 c2 d2 e3 b4 f4 g5.
Black: king f8, queen a1, rook g7 e8, bishop d3 d8, knight c4 b8, pawn b5 f5 e6 a7 c7 d7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Black are ahead by 5 points of material (32 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 f1, the black king on f8.
It is White to move on move 15, with 6 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): h — natural highways for the rooks and queen.
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
15. cxd3 Nxe3+ 16. Ke2 Qb2 17. Rb1 Qa3 18. Bxe8
Why it works
- Great move! pawn to d3 keeps the pressure (+2.9).
- king to e2 develops smoothly.
- A natural move: rook to b1.
- Best move. bishop to e8 is exactly what the engine plays (+4.2).
- You win a piece — the rook.
- If instead Nxe3+, then Ke2 and you stay on top.
Move by move
- 15. cxd3 — pawn to d3 (capture)
- Nxe3+ — knight to e3 (capture) with check
- 16. Ke2 — king to e2
- Qb2 — queen to b2
- 17. Rb1 — rook to b1
- Qa3 — queen to a3
- 18. Bxe8 — bishop to e8 (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.
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 #81.
SP-81 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on f1, the rooks on e1 and g1, the queen on h1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
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 BastionGuard family; read right to left it becomes position 875.
The engine's main line opens with g4.
Morozov Balance Index: 24 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +35 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #81Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-81
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