Attack on the uncastled king: king to d3 (e2·3)
c9-26824naming 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 1390 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 e2, queen f5, rook c1, bishop a1, knight f2 h3, pawn a2 d2 b3 e3 c4 h6.
Black: king e8, queen h2, rook g3 c8, bishop f3 f8, pawn c5 b6 a7 d7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Material is level — 29 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on e2, the black king on e8.
It is White to move on move 18, with 4 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 6 pawns, Black 4. Files fully open (no pawns of either colour): f, g — natural highways for the rooks and queen.
Black 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
18. Kd3 O-O-O 19. h7 Bd6 20. h8=Q Rxh8 21. Bxh8
Why it works
- Great move! king to d3 keeps the pressure (+3.0).
- Spot on — pawn to h7 (+3.2).
- A natural move: pawn to h8.
- Great move! bishop to h8 keeps the pressure (+3.5).
- You win a piece — the rook.
- If instead O-O-O, then h7 and you stay on top.
Move by move
- 18. Kd3 — king to d3
- O-O-O — king to c8
- 19. h7 — pawn to h7
- Bd6 — bishop to d6
- 20. h8=Q — pawn to h8
- Rxh8 — rook to h8 (capture)
- 21. Bxh8 — bishop to h8 (capture)
Types in this puzzle
Promotion
The pawn reaches the last rank and becomes a queen — decisively.
Promotion turns a pawn on the last rank into a queen and rewrites the evaluation on the spot. In tactics the passer rarely walks in for free — usually a sacrifice clears its path. Count the tempi: how many moves does the pawn need, and can the defender stop it in time? And watch the promotion square itself — it must be out of enemy reach or won by force in your combination.
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 #578.
SP-578 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on c1 and g1, the queen on b1.
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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 279.
The engine's main line opens with c4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +56 centipawns for White (depth 46, 400 000 000 nodes).
In 50 self-play games White scored 62.0% (95% CI 48.2–74.1%).
Explore position #578Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-578
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