Winning blow: pawn to f5 (g4·9)
c9-24977naming 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 1200 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 b1, queen d1, rook h3 c5, bishop h1 f4, knight b5, pawn b2 a4 d4 g4.
Black: king b8, queen d8, rook a8 e8, bishop f5, knight b4 d5, pawn a5 h6 b7 c7 f7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Black are ahead by 1 points of material (32 against 33; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 25, with 8 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 4 pawns, Black 5. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: c, f, h.
White hold the bishop pair, an edge in open lines. The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. gxf5 Nxf4 26. Rxc7 Nbd5 27. Rc5 Ra6 28. Bxd5
Why it works
- Great move! pawn to f5 keeps the pressure (+2.6).
- Spot on — rook to c7 (+1.8).
- A natural move: rook to c5.
- Best move. bishop to d5 is exactly what the engine plays (+2.6).
- You win a piece — the bishop.
- If instead Nxf4, then Rxc7 and you stay on top.
Move by move
- 25. gxf5 — pawn to f5 (capture)
- Nxf4 — knight to f4 (capture)
- 26. Rxc7 — rook to c7 (capture)
- Nbd5 — knight to d5
- 27. Rc5 — rook to c5
- Ra6 — rook to a6
- 28. Bxd5 — bishop to d5 (capture)
Types in this puzzle
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
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.
Overload
One defender guards two things — it cannot do both jobs.
Overloading exploits a defender with two jobs at once — guarding a piece and covering a mating square, for instance. It cannot do both: your first strike forces it to handle one duty and abandon the other. Find the overworked piece by asking what happens to each of its charges if it gets distracted. Then hit one target and collect the other — an overloaded defender only pretends to defend.
About this position
These pieces come from starting position #639.
SP-639 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on a1 and e1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 224.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #639Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-639
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