Winning blow: knight to c7 (b5·12)
c9-22190naming 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 1930 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 c1, queen b2, rook d1, bishop f1, knight b5 c5, pawn c2 g2 e3 a4 d4 h4.
Black: king b8, queen a5, rook d8, bishop d6 e8, knight f6 g6, pawn f3 d5 h5 e6 c7 f7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 3 points of material (29 against 32; 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 b8.
It is White to move on move 17, with 32 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: f.
Black hold the bishop pair, an edge in open lines. The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
17. Nxc7+ Bb5 18. Nxb5 Bxc5 19. dxc5 Ka8 20. Qxf6
Why it works
- Great move! knight to c7 keeps the pressure (+4.4).
- Well found: knight to b5 (+4.2).
- Strong! pawn to c5 is the sharp choice (+4.5).
- Great move! queen to f6 keeps the pressure (+5.4).
- You win a piece — the bishop.
- If instead Bb5, then Nxb5 and you win the bishop.
Move by move
- 17. Nxc7+ — knight to c7 (capture) with check
- Bb5 — bishop to b5
- 18. Nxb5 — knight to b5 (capture)
- Bxc5 — bishop to c5 (capture)
- 19. dxc5 — pawn to c5 (capture)
- Ka8 — king to a8
- 20. Qxf6 — queen to f6 (capture)
Types in this puzzle
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
About this position
These pieces come from starting position #874.
SP-874 · BastionScout — A knight on the a- or h-file, king on c or f — the mirror twin lands here as well.
The king starts on c1, the rooks on b1 and d1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 85.
The engine's main line opens with b4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #874Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-874
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