Attack on the uncastled king: bishop to b6 (c5·2)
c9-14306naming 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 1930 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 c1, rook e1 c3, bishop c5, knight e5, pawn d2 h2 d3 g3 b4 f4.
Black: king d8, rook c8 e8, bishop h8, knight d5, pawn f5 a6 g6 d7 e7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Material is level — 22 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on c1, the black king on d8.
It is White to move on move 20, with 35 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): c — natural highways for the rooks and queen. Half-open for White: a, e.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
20. Bb6+ Rc7 21. Nf7+ Kc8 22. Nd6+ Kd8 23. Nxe8
Why it works
- Great move! bishop to b6 keeps the pressure (+5.1).
- Spot on — knight to f7 (+5.3).
- Strong! knight to d6 is the sharp choice (+5.4).
- Best move. knight to e8 is exactly what the engine plays (+4.8).
- You win a piece — the rook.
- If instead Rc7, then Nf7+ and you stay on top.
Move by move
- 20. Bb6+ — bishop to b6 with check
- Rc7 — rook to c7
- 21. Nf7+ — knight to f7 with check
- Kc8 — king to c8
- 22. Nd6+ — knight to d6 with check
- Kd8 — king to d8
- 23. Nxe8 — knight to e8 (capture)
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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.
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
About this position
These pieces come from starting position #335.
SP-335 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on d1, the rooks on b1 and e1, the queen on c1.
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 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: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 336.
The engine's main line opens with f4.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #335Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-335
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