Attack on the uncastled king: queen to a6 (c6·2)
c9-22046naming 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 1200 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 c1, queen c6, rook b1 f1, bishop a1, knight d3, pawn a2 c2 d2 h2 e3 b4.
Black: king c8, queen g6, rook b8 f8, bishop d8, knight f6, pawn b5 e5 e6 a7 c7 g7 h7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Black are ahead by 1 points of material (31 against 32; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on c8.
It is White to move on move 15, with 49 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: g.
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. Qa6+ Rb7 16. Nc5 Qg2 17. Qxe6+ Nd7 18. Qxd7+
Why it works
- Best move. queen to a6 is exactly what the engine plays (#6).
- Well found: knight to c5 (#5).
- Strong! queen to e6 is the sharp choice (#4).
- Great move! queen to d7 keeps the pressure (#3).
- You win a piece — the knight.
- If instead Rb7, then Nc5 and you stay on top.
Move by move
- 15. Qa6+ — queen to a6 with check
- Rb7 — rook to b7
- 16. Nc5 — knight to c5
- Qg2 — queen to g2
- 17. Qxe6+ — queen to e6 (capture) with check
- Nd7 — knight to d7
- 18. Qxd7+ — queen to d7 (capture) with check
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.
About this position
These pieces come from starting position #849.
SP-849 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and f1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 107.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #849Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-849
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads