Attack on the uncastled king: bishop to c5 (a3)
c9-11561naming 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 f1, queen f2, rook e1 g1, bishop d1 a3, knight c2, pawn a2 g2 h2 b3 e5 g6.
Black: king f8, queen b8, rook e8 h8, bishop c7 c8, knight d7, pawn h4 c5 a6 f6 b7 g7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
Material is level — 34 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on f1, the black king on f8.
It is White to move on move 19, 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): d — natural highways for the rooks and queen. Half-open for White: c, f.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
19. Bxc5+ Nxc5 20. Qxc5+ Bd6 21. exd6 Rxe1+ 22. Kxe1
Why it works
- Best move. bishop to c5 is exactly what the engine plays (+4.0).
- Well found: queen to c5 (+4.4).
- Precise: pawn to d6 is the top choice (+6.0).
- Best move. king to e1 is exactly what the engine plays (+6.2).
- You win a piece — the rook.
- If instead Nxc5, then Qxc5+ and you stay on top.
Move by move
- 19. Bxc5+ — bishop to c5 (capture) with check
- Nxc5 — knight to c5 (capture)
- 20. Qxc5+ — queen to c5 (capture) with check
- Bd6 — bishop to d6
- 21. exd6 — pawn to d6 (capture)
- Rxe1+ — rook to e1 (capture) with check
- 22. Kxe1 — king to e1 (capture)
Types in this puzzle
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
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 #309.
SP-309 · BastionScout — Off-centre king plus a rim knight (a/h): 168 positions carry this shape.
The king starts on f1, the rooks on e1 and g1, the queen on b1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 362.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #309Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-309
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