Winning blow: knight to b5 (a7·3)
c9-09048naming 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 1010 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 c3, rook b1 d1, knight c2 a7, pawn a2 e2 h2 g3 d4 f4.
Black: king c7, queen h8, rook d8, bishop a8, knight d7, pawn e4 c6 e6 g6 f7 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 5 points of material (31 against 26; 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 c7.
It is White to move on move 20, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): b — 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
20. Nb5+ Kb8 21. Nd6+ Kc7 22. Nxf7
Why it works
- Great move! knight to b5 keeps the pressure (+10.1).
- Spot on — knight to d6 (+10.5).
- Precise: knight to f7 is the top choice (+10.6).
- You win decisive material (+10.6).
- If instead Kc8, then Nd6+ and you stay on top.
Move by move
- 20. Nb5+ — knight to b5 with check
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 #947.
SP-947 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and d1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 3.
The engine's main line opens with g3.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #947Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-947
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