Chess960 tactic on f6 (g5)
c9-09436naming 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.
Mate: a forcing sequence that ends the game — the king has no escape.
Mate in 4: a forced checkmate in four moves — every reply is covered.
Difficulty 2120 ShuffleRating — expert level — few solve it at first try.
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 is a forced mating attack. Start from the enemy king: which of its squares are already covered, and which move takes away the rest while keeping the king in check? Forcing moves — checks and captures — are what turn an attack into mate.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
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, queen d2, rook d1 f1, bishop c1 g2, knight c5 e5, pawn b2 e2 f2 g3 d4 g5.
Black: king g7, queen a2, rook e8 g8, bishop h8, knight b4 c7, pawn c6 f6 a7 e7 h7.
14 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 4 points of material (37 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 g1, the black king on g7.
It is White to move on move 21, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a, c, 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
21. gxf6+ Kxf6 22. Qh6+ Rg6 23. Bg5+ Kf5 24. Bh3#
Why it works
- Great move! pawn to f6 keeps the pressure (#2).
- Spot on — queen to h6 (#2).
- Precise: bishop to g5 is the top choice (#1).
- Best move. bishop to h3 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kxf6, then Qh6+ and you stay on top.
Move by move
- 21. gxf6+ — pawn to f6 (capture) with check
- Kxf6 — king to f6 (capture)
- 22. Qh6+ — queen to h6 with check
- Rg6 — rook to g6
- 23. Bg5+ — bishop to g5 with check
- Kf5 — king to f5
- 24. Bh3# — bishop to h3 and it is checkmate
Types in this puzzle
Two-bishop mate
The bishop pair sweeps two adjacent diagonals — the king has nowhere to hide.
The two-bishop mate rakes two adjacent diagonals: one bishop mates while the other seals off the escape squares. The bishops complement each other perfectly — living on opposite colors, together they cover an unbroken strip of the board. The pattern usually appears at the edge or in the corner where the king was pressed beforehand. Treasure the bishop pair until the attack comes — on an open board two adjacent diagonals become a solid wall.
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
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.
About this position
These pieces come from starting position #215.
SP-215 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on e1, the rooks on d1 and g1, the queen on b1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
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 e2, f2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 642.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 91 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 centipawns for White (depth 51, 400 000 000 nodes).
Explore position #215Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-215
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