Attack on the uncastled king: bishop to b7 (a6·5)
c9-19485naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 e1, rook a1 d1, bishop a6 f6, knight f2, pawn c2 d2 g2 h2 e3 b4 f4.
Black: king c8, queen e8, rook b8 d8, bishop b7 f8, knight f7, pawn a4 f5 d6 e6 h6 c7 g7.
14 white and 14 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Material is level — 35 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 c8.
It is White to move on move 13, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a.
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
13. Bxb7+ Rxb7 14. Bxd8
Why it works
- Brilliant! The bishop on b7 is a sacrifice that works — you stand better (+2.9).
- A brilliant blow: bishop to d8, and you stand better (+2.7).
- You win a piece — the rook.
- If instead Rxb7, then Bxd8 and you win the rook.
Move by move
- 13. Bxb7+ — bishop to b7 (capture) with check
- Rxb7 — rook to b7 (capture)
- 14. Bxd8 — bishop to d8 (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.
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 #914.
SP-914 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins in a corner.
The king starts on c1, the rooks on b1 and d1, the queen on e1.
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.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 39.
The engine's main line opens with Ng3, bringing the knight out to g3.
Morozov Balance Index: 13 of 100 — class D — largest edge. Engine evaluation of the starting position: +41 centipawns for White (depth 41, 400 000 000 nodes).
Explore position #914Provenance
Mined from the project's engine self-play games.
Pack 005 · SP-914
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