Chess960 tactic on c7 (g7)
c9-11993naming 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 2400 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 f1, queen g7, rook c1 g1, knight e4, pawn b2 f2 d3 g3 f5.
Black: king b5, rook e8 h8, knight d4, pawn a5 e5 f6 b7 c7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 9 points of material (27 against 18; 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 b5.
It is White to move on move 25, with 39 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): h — natural highways for the rooks and queen. Half-open for White: a, c, 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
25. Qxc7 Rh7 26. Rc5+ Kb4 27. Qxa5+ Kb3 28. Qa3#
Why it works
- Best move. queen to c7 is exactly what the engine plays (#3).
- Spot on — rook to c5 (#2).
- Precise: queen to a5 is the top choice (#1).
- Best move. queen to a3 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Rh7, then Rc5+ and you stay on top.
Move by move
- 25. Qxc7 — queen to c7 (capture)
- Rh7 — rook to h7
- 26. Rc5+ — rook to c5 with check
- Kb4 — king to b4
- 27. Qxa5+ — queen to a5 (capture) with check
- Kb3 — king to b3
- 28. Qa3# — queen to a3 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
About this position
These pieces come from starting position #85.
SP-85 · BastionScout — A c- or f-file king with at least one knight out on the edge.
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.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 874.
The engine's main line opens with h4.
Morozov Balance Index: 96 of 100 — class A — most balanced. Engine evaluation of the starting position: +8 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #85Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-85
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