Winning blow: rook to a8 (e8·4)
c9-18969naming 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 1870 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 d2, queen g3, rook b2 e8, bishop g1, pawn h2 c3 f6 g7.
Black: king b7, queen a5, rook a8, bishop d3, pawn b5 c6 a7 d7 h7.
9 white and 9 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
White are ahead by 4 points of material (26 against 22; 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 b7.
It is White to move on move 30, with 54 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): e — natural highways for the rooks and queen. Half-open for White: a, b, d.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. Rxa8 Qxc3+ 31. Kxc3 c5 32. Rb8+
Why it works
- Great move! rook to a8 keeps the pressure (#5).
- Well found: king to c3 (#4).
- Precise: rook to b8 is the top choice (#4).
- You win a piece — the queen.
- If instead c5, then Qd6 and you win the rook.
Move by move
- 30. Rxa8 — rook to a8 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
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 014 · SP-638
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