Attack on the uncastled king: rook to e6 (e3·4)
c9-13224naming 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 1870 ShuffleRating — for advanced tacticians.
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 d1, rook a1 e3, bishop h1 a3, knight g1 c3, pawn a2 c2 h2 b3 d3 f4.
Black: king d8, rook e6 a8, bishop c8 h8, knight b8 g8, pawn f5 d6 a7 b7 c7 h7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Material is level — 28 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 11, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): e, g — natural highways for the rooks and queen.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
11. Rxe6 Bxc3 12. O-O-O Nc6 13. Re3
Why it works
- Great move! rook to e6 keeps the pressure (+4.2).
- king to c1 develops smoothly.
- A natural move: rook to e3.
- You reach a winning position (+4.2).
- If instead Bxc3, then O-O-O and you stay on top.
Move by move
- 11. Rxe6 — rook to e6 (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.
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #631.
SP-631 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on a1 and f1, the queen on e1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 226.
The engine's main line opens with Nc3, bringing the knight out to c3.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #631Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-631
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