Winning blow: king to a2 (b1·22)
c9-26478naming 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 1200 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 b1, queen e3, rook a1 f1, knight d6 g6, pawn b2 a3 d3 h5.
Black: king b8, queen g7, rook e8, bishop a2, knight c6, pawn a5 b7 c7.
10 white and 8 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 6 points of material (29 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 b1, the black king on b8.
It is White to move on move 33, with 4 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): e, f, g — natural highways for the rooks and queen. Half-open for White: c.
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
33. Kxa2 Rxe3 34. Rf8+ Ka7 35. Nf5 Qd7 36. Nxe3
Why it works
- Great move! king to a2 keeps the pressure (+2.8).
- Well found: rook to f8 (+3.0).
- Strong! knight to f5 is the sharp choice (+3.0).
- Great move! knight to e3 keeps the pressure (+2.7).
- You reach a winning position (+2.7).
- If instead Rxe3, then Rf8+ and you stay on top.
Move by move
- 33. Kxa2 — king to a2 (capture)
- Rxe3 — rook to e3 (capture)
- 34. Rf8+ — rook to f8 with check
- Ka7 — king to a7
- 35. Nf5 — knight to f5
- Qd7 — queen to d7
- 36. Nxe3 — knight to e3 (capture)
Types in this puzzle
Knight fork
One knight move attacks two targets at once — the opponent can only save one.
A fork is one move that attacks two targets at once, and no piece forks better than the knight. Look through the knight's eyes: it jumps in an L and never moves along straight lines, which is exactly why its threats get missed. Both victims of a knight fork always stand on squares of one color, while the knight strikes from the opposite color. Hunt for the square from which the knight hits the king and a heavy piece at once.
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
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 008 · SP-638
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