Attack on the uncastled king: pawn to b5 (c4·21)
c9-06018naming 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.
An opening trap from this Chess960 starting position.
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 780 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.
Early Chess960 traps punish natural but careless development. Look for a forcing move that exploits a piece the opponent has just placed on a poor square — a fork, a pin or a threat that wins material before either side is fully developed.
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 d1, queen c1, rook b1 h1, bishop e1 f1, knight a1 f3, pawn a2 b2 f2 g2 h2 d3 c4.
Black: king d8, queen b5, rook b8 h8, bishop e8 f8, knight a8 g8, pawn a7 b7 c7 e7 f7 g7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 6.
The position in numbers
Material is level — 38 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on d1, the black king on d8.
It is White to move on move 6, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: e.
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
6. cxb5 Nf6 7. Be2 O-O-O 8. Bd2
Why it works
- Great move! pawn to b5 keeps the pressure (+6.9).
- bishop to e2 develops smoothly.
- A natural move: bishop to d2.
- You win a piece — the queen.
- If instead O-O-O, then Be2 and you win the queen.
Move by move
- 6. cxb5 — pawn to b5 (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.
Early trap
In the first moves of a fresh setup a trap already snaps shut.
An early trap is a tactic that snaps shut within the first moves: an unfamiliar setup hides shots that classical openings never produce. Examine every starting position with fresh eyes — which pieces already aim at each other, what hangs after the first pawn moves. Moves that feel "safe" from classical habit can lose on the spot here. Chess960 has no opening theory; it has alertness from move one.
About this position
These pieces come from starting position #234.
SP-234 · 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 h1, 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.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 629.
The engine's main line opens with d3.
Morozov Balance Index: 24 of 100 — class D — largest edge. Engine evaluation of the starting position: +35 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #234Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 002 · SP-234
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