Winning blow: knight to c6 (e7·4)
c9-17085naming 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 1060 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 g1, rook e1, knight e7, pawn f2 g2 b3 a4 b6.
Black: king h8, queen c6, rook d8, knight h4, pawn e5 a6 d6 f6 f7.
8 white and 9 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
Black are ahead by 9 points of material (13 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 g1, the black king on h8.
It is White to move on move 23, with 25 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): c, h — natural highways for the rooks and queen. Half-open for White: d, e.
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
23. Nxc6 Rc8 24. b7 Rxc6 25. b8=Q+
Why it works
- Great move! knight to c6 keeps the pressure (+4.9).
- Spot on — pawn to b7 (+5.0).
- Precise: pawn to b8 is the top choice (+4.8).
- You win a piece — the queen.
- If instead Rc8, then b7 and you win the queen.
Move by move
- 23. Nxc6 — knight to c6 (capture)
- Rc8 — rook to c8
- 24. b7 — pawn to b7
- Rxc6 — rook to c6 (capture)
- 25. b8=Q+ — pawn to b8 with check
Types in this puzzle
Promotion
The pawn reaches the last rank and becomes a queen — decisively.
Promotion turns a pawn on the last rank into a queen and rewrites the evaluation on the spot. In tactics the passer rarely walks in for free — usually a sacrifice clears its path. Count the tempi: how many moves does the pawn need, and can the defender stop it in time? And watch the promotion square itself — it must be out of enemy reach or won by force in your combination.
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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
About this position
These pieces come from starting position #580.
SP-580 · 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 f1, the rooks on d1 and g1, the queen on a1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-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 286.
The engine's main line opens with Ng3, bringing the knight out to g3.
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 #580Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-580
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