Attack on the uncastled king: pawn to b5 (b4·2)
c9-19530naming 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 1110 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 b1, rook c1 h1, bishop f1 d4, pawn a2 c2 f2 g2 h2 e3 b4 e5.
Black: king d8, queen b7, rook c8 h8, bishop c6, knight d7, pawn d5 b6 e6 a7 c7 f7 g7 h7.
14 white and 14 black pieces are on the board; the puzzle position arises after move 14.
The position in numbers
Material is level — 33 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 d8.
It is White to move on move 14, with 30 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d.
White 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
14. b5 Bxb5 15. Qxb5
Why it works
- Great move! pawn to b5 keeps the pressure (+3.5).
- Spot on — queen to b5 (+3.3).
- You reach a winning position (+3.3).
- If instead Bxb5, then Qxb5 and you stay on top.
Move by move
- 14. b5 — pawn to b5
- Bxb5 — bishop to b5 (capture)
- 15. Qxb5 — queen to b5 (capture)
Types in this puzzle
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
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.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #218.
SP-218 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on c1 and h1, the queen on b1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneScout family; read right to left it becomes position 645.
The engine's main line opens with d3.
Morozov Balance Index: 75 of 100 — class A — most balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #218Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-218
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