Attack on the uncastled king: bishop to b7 (g2·2)
c9-26774naming 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.
A piece strikes across the board from its Chess960 starting square.
A fork made possible by the Chess960 piece placement.
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 1290 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.
From some Chess960 setups a bishop or queen rakes a long diagonal straight from move one. Trace those long-range lines into the enemy camp: a single opened file or diagonal can create an immediate pin, skewer or mating threat.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 e1, queen h1, rook a1, bishop c1 g2, knight c3, pawn a2 b2 c2 d2 e2 f2 h4 h5.
Black: king e8, queen h8, rook a8, bishop c8 f8, knight e6 b8, pawn g4 d6 a7 b7 c7 e7.
14 white and 13 black pieces are on the board; the puzzle position arises after move 9.
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 e1, the black king on e8.
It is White to move on move 9, with 31 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: g.
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
9. Bxb7 Bxb7 10. Qxb7 Kd7 11. Qxa8
Why it works
- Great move! bishop to b7 keeps the pressure (+2.3).
- Well found: queen to b7 (+2.6).
- Precise: queen to a8 is the top choice (+2.6).
- You win a piece — the rook.
- If instead Bxb7, then Qxb7 and you stay on top.
Move by move
- 9. Bxb7 — bishop to b7 (capture)
- Bxb7 — bishop to b7 (capture)
- 10. Qxb7 — queen to b7 (capture)
- Kd7 — king to d7
- 11. Qxa8 — queen to a8 (capture)
Types in this puzzle
Long-range opener
From its unusual home square a long-range piece strikes across the board.
The long-range opener: a bishop, rook or queen strikes across the whole board straight from its starting area. In Chess960 the long-range pieces sit on unfamiliar squares, and a single pawn move can uncover a shot deep into the enemy camp. In the opening, trace with your eyes the diagonals and files of every long-range piece — yours and theirs. The mistake is pushing a pawn without checking whose line you have just opened.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
Bishop fork
The bishop attacks two pieces on crossing diagonals at once.
A bishop fork happens when the bishop lands where two diagonals cross and attacks a target on each of them. Both victims must stand on the bishop's color — that is the first thing to verify. Scan for loose enemy pieces that share the color of squares with their own king or queen. A common sin is placing your own pieces on squares of one color and handing your opponent exactly this geometry.
About this position
These pieces come from starting position #470.
SP-470 · ThroneGuard — The king starts in the middle of the back rank, on d or e, and neither knight begins in a corner.
The king starts on e1, the rooks on a1 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.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: c2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 678.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 16 of 100 — class D — largest edge. Engine evaluation of the starting position: +39 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #470Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-470
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