Winning blow: pawn to f6 (g5·18)
c9-14345naming 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 1870 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 f1, queen f4, rook c1 g1, bishop a1 b1, pawn a2 b2 d2 e2 f2 h2 c4 g5.
Black: king f8, queen f6, rook e8 g8, bishop a8, knight b5, pawn h5 a7 b7 e7.
14 white and 10 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
White are ahead by 4 points of material (33 against 29; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f8.
It is White to move on move 18, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 4. No file is fully open, so the heavy pieces have to be pried in.
White hold the bishop pair, an edge in open lines. 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
18. gxf6 Rxg1+ 19. Kxg1 Kf7 20. fxe7+
Why it works
- Great move! pawn to f6 keeps the pressure (+11.8).
- Spot on — king to g1 (#13).
- Strong! pawn to e7 is the sharp choice (#11).
- You win a piece — the queen.
- If instead Nd6, then Rxg8+ and you win the queen.
Move by move
- 18. gxf6 — pawn 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.
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.
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
About this position
These pieces come from starting position #80.
SP-80 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on f1, the rooks on e1 and g1, the queen on h1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 879.
The engine's main line opens with g4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +83 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 #80Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-80
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