Winning blow: queen to b7 (a6·5)
c9-22049naming 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 1930 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 b1, queen a6, rook d1 e1, bishop f4, knight c5, pawn a2 b2 c2 h2 f3.
Black: king c7, queen d7, rook d6 h8, bishop f8, knight f5, pawn b5 d5 h5 g6.
11 white and 10 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 1 points of material (30 against 29; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on c7.
It is White to move on move 33, with 51 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: d, 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
33. Qb7+ Kd8 34. Bg5+ Be7 35. Qb8+ Qc8 36. Bxe7+
Why it works
- Best move. queen to b7 is exactly what the engine plays (#9).
- Spot on — bishop to g5 (#8).
- Strong! queen to b8 is the sharp choice (#7).
- Best move. bishop to e7 is exactly what the engine plays (#6).
- You win a piece — the bishop.
- If instead Kd8, then Bg5+ and you stay on top.
Move by move
- 33. Qb7+ — queen to b7 with check
- Kd8 — king to d8
- 34. Bg5+ — bishop to g5 with check
- Be7 — bishop to e7
- 35. Qb8+ — queen to b8 with check
- Qc8 — queen to c8
- 36. Bxe7+ — bishop to e7 (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.
Check chase
Every move is a check — the king is chased into losing ground.
In a check chase every one of your moves is a check, so the opponent never gets a free second. The king is herded across the board until it loses a piece or walks into a decisive blow. Such lines are the easiest to calculate: each check allows only a handful of replies, so try them all. Make it a habit to start calculating any sharp position with the checks — they are the most forcing moves on the board.
About this position
These pieces come from starting position #630.
SP-630 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on a1 and g1, the queen on e1.
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: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 230.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +51 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #630Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-630
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