Attack on the uncastled king: bishop to d5 (e6)
c9-17592naming 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 1060 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 e1, queen a2, rook b1 f1, bishop e6, knight g4, pawn c2 d2 e2 g2 h2 a3 f3.
Black: king e8, queen e7, rook d8 f8, knight a7 h8, pawn a5 b5 d5 e5 b6 g6 h7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Material is level — 32 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on e1, the black king on e8.
It is White to move on move 20, with 40 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: b.
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
20. Bxd5 Nf7 21. c4 Nd6 22. cxb5
Why it works
- Great move! bishop to d5 keeps the pressure (+3.7).
- pawn to c4 develops smoothly.
- Precise: pawn to b5 is the top choice (+3.6).
- You reach a winning position (+3.6).
- If instead Nf7, then c4 and you stay on top.
Move by move
- 20. Bxd5 — bishop to d5 (capture)
- Nf7 — knight to f7
- 21. c4 — pawn to c4
- Nd6 — knight to d6
- 22. 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.
About this position
These pieces come from starting position #300.
SP-300 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on e1, the rooks on d1 and f1, the queen on a1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 380.
The engine's main line opens with Ng3, bringing the knight out to g3.
Morozov Balance Index: 98 of 100 — class A — most balanced. Engine evaluation of the starting position: 0 centipawns for White (depth 49, 400 000 000 nodes).
In 50 self-play games White scored 53.0% (95% CI 39.5–66.1%).
Explore position #300Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-300
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