Winning blow: knight to b3 (a1·3)
c9-23531naming 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 1290 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 c1, queen c2, rook d1, bishop g1 c6, knight a1, pawn a2 e2 g2 c3 g3 b5.
Black: king a5, queen f8, rook d8, bishop b6 g8, knight e5, pawn c5 d6 a7 g7 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 1 points of material (29 against 28; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on a5.
It is White to move on move 21, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: d, h.
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
21. Nb3+ Bxb3 22. axb3 Nd3+ 23. exd3
Why it works
- Best move. knight to b3 is exactly what the engine plays (+6.3).
- Well found: pawn to b3 (#4).
- Precise: pawn to d3 is the top choice (#3).
- You win a piece — the bishop.
- If instead Bxb3, then axb3 and you stay on top.
Move by move
- 21. Nb3+ — knight to b3 with check
- Bxb3 — bishop to b3 (capture)
- 22. axb3 — pawn to b3 (capture)
- Nd3+ — knight to d3 with check
- 23. exd3 — pawn to d3 (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 #348.
SP-348 · 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 c1 and f1, the queen on e1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
The second rank carries 2 pawns with no defender at all: b2, g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 332.
The engine's main line opens with f4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +62 centipawns for White (depth 43, 400 000 000 nodes).
In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
Explore position #348Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-348
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