Winning blow: bishop to d7 (b5·6)
c9-24905naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1790 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.
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 b2, rook d1, bishop b5 d6, knight e6, pawn c2 g2 e3 h4.
Black: king c8, queen a5, knight a6 h8, pawn f5 b7 d7 g7 h7.
9 white and 9 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
Black are ahead by 2 points of material (18 against 20; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on c8.
It is White to move on move 30, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 5. Files fully open (no pawns of either colour): a — natural highways for the rooks and queen. Half-open for White: b, d, f.
White hold the bishop pair, an edge in open lines. 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
30. Bxd7+ Kxd7 31. Bb4+ Kxe6 32. Bxa5
Why it works
- Great move! bishop to d7 keeps the pressure (+3.6).
- Spot on — bishop to b4 (+3.6).
- Strong! bishop to a5 is the sharp choice (+3.6).
- You win a piece — the queen.
- If instead Kxd7, then Bb4+ and you stay on top.
Move by move
- 30. Bxd7+ — bishop to d7 (capture) with check
- Kxd7 — king to d7 (capture)
- 31. Bb4+ — bishop to b4 with check
- Kxe6 — king to e6 (capture)
- 32. Bxa5 — bishop to a5 (capture)
Types in this puzzle
Sacrifice attack
Give up material to unleash a decisive attack.
A sacrificial attack gives up material on purpose to rip the king's shelter open and launch a decisive assault. The sac is sound when you get concrete assets in return: open lines to the king, tempi, pieces ready to pour in. The signs: a poorly sheltered king, your forces aimed at its home, defenders stranded far away. The iron rule is to calculate, not hope — once the material is gone, there is no way back.
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.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
About this position
These pieces come from starting position #638.
SP-638 · 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 a1 and e1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionScout family; read right to left it becomes position 228.
The engine's main line opens with f4.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #638Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-638
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