Winning blow: pawn to b7 (a6·5)
c9-21574naming 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 1060 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.
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 d2, rook e1, bishop f2 f5, pawn h3 g4 b5 a6.
Black: king f7, queen b7, rook g8, knight e6 c7, pawn c5 d6 h7.
8 white and 8 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
Black are ahead by 8 points of material (15 against 23; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d2, the black king on f7.
It is White to move on move 38, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen. Half-open for White: c, d.
White hold the bishop pair, an edge in open lines. The White king has 7 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
38. axb7 Rb8 39. b6 Rxb7 40. bxc7
Why it works
- Great move! pawn to b7 keeps the pressure (+4.3).
- pawn to b6 develops smoothly.
- Strong! pawn to c7 is the sharp choice (+4.5).
- You win a piece — the queen.
- If instead Rb8, then b6 and you win the queen.
Move by move
- 38. axb7 — pawn to b7 (capture)
- Rb8 — rook to b8
- 39. b6 — pawn to b6
- Rxb7 — rook to b7 (capture)
- 40. bxc7 — pawn to c7 (capture)
Types in this puzzle
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
About this position
These pieces come from starting position #166.
SP-166 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on e1, the rooks on b1 and h1, the queen on g1.
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: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 790.
The engine's main line opens with Nb3, bringing the knight out to b3.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #166Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-166
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