Attack on the uncastled king: bishop to a8 (e4·9)
c9-20699naming 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 d1, queen e1, rook b1 g2, bishop a1 e4, knight c2 d3, pawn a2 b2 d2 g3 c4 f4 h4.
Black: king d8, queen h8, rook b8 f8, bishop d4 a8, knight f5 g7, pawn g4 b6 d6 h6 a7 c7 f7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 15.
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 15, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen.
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
15. Bxa8 Rxa8 16. Qe4 Re8 17. Qxa8+
Why it works
- Great move! bishop to a8 keeps the pressure (+3.6).
- queen to e4 develops smoothly.
- Strong! queen to a8 is the sharp choice (+4.1).
- You win a piece — the rook.
- If instead Rxa8, then Qe4 and you stay on top.
Move by move
- 15. Bxa8 — bishop to a8 (capture)
- Rxa8 — rook to a8 (capture)
- 16. Qe4 — queen to e4
- Re8 — rook to e8
- 17. Qxa8+ — queen to a8 (capture) with check
Types in this puzzle
Queen fork
The queen lands on a square from which it attacks two targets at once.
The queen strikes along files, ranks and diagonals, so she forks more often than any other piece. Look for a square where the queen attacks two undefended targets at once — most often a check combined with a loose piece. Diagonal blows are especially venomous: a slanting check that also eyes a rook in the corner is the classic of the genre. Remember that both targets must be unprotected, or your «fork» is just a shot into the air.
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.
Winning exchange
A forced series of captures on one square ends in your favour.
A winning exchange is a forced series of captures on one square that leaves you ahead in material. It is pure arithmetic: count the attackers and defenders of the square and note the value of every piece in the queue. Capture in the right order — cheap pieces first, expensive ones later — or a winning trade turns into a losing one. The classic error is stopping the count halfway and missing the opponent's final recapture.
About this position
These pieces come from starting position #562.
SP-562 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on d1, the rooks on b1 and g1, the queen on h1.
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: f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 487.
The engine's main line opens with b3.
Morozov Balance Index: 59 of 100 — class B — balanced. Engine evaluation of the starting position: +24 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #562Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-562
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