Winning blow: bishop to c7 (a5·4)
c9-11404naming 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 fork made possible by the Chess960 piece placement.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 2400 ShuffleRating — expert level — few solve it at first try.
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.
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.
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 a4, rook f3, bishop a5, pawn b2 e2 h2 d4 g4 f5.
Black: king a8, queen g8, rook b8 f8, bishop e5, pawn d5 g5 c6 c7 f7 h7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
Black are ahead by 5 points of material (23 against 28; 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 a8.
It is White to move on move 26, with 37 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): a — natural highways for the rooks and queen. Half-open for White: c.
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
26. Bxc7+ Kb7 27. Bxe5 f6 28. Rb3+ Kc8 29. Rxb8+
Why it works
- Best move. bishop to c7 is exactly what the engine plays (#4).
- Spot on — bishop to e5 (#3).
- Precise: rook to b3 is the top choice (#2).
- Best move. rook to b8 is exactly what the engine plays (#1).
- You win a piece — the rook.
- If instead Kb7, then Bxe5 and you win the bishop.
Move by move
- 26. Bxc7+ — bishop to c7 (capture) with check
- Kb7 — king to b7
- 27. Bxe5 — bishop to e5 (capture)
- f6 — pawn to f6
- 28. Rb3+ — rook to b3 with check
- Kc8 — king to c8
- 29. Rxb8+ — rook to b8 (capture) with check
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
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.
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
About this position
These pieces come from starting position #471.
SP-471 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on e1, the rooks on a1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
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: c2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 674.
The engine's main line opens with d3.
Morozov Balance Index: 100 of 100 — class A — most balanced. Engine evaluation of the starting position: 0 centipawns for White (depth 47, 400 000 000 nodes).
In 50 self-play games White scored 50.0% (95% CI 36.6–63.4%).
Explore position #471Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-471
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