Winning blow: bishop to g5 (h6·4)
c9-15907naming 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 in 4: a forced checkmate in four moves — every reply is covered.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 2250 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.
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.
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 c4, queen e8, bishop h6, pawn a2 f2.
Black: king d6, pawn e4 g5 a7.
5 white and 4 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
White are ahead by 11 points of material (14 against 3; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c4, the black king on d6.
It is White to move on move 36, with 30 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 2 pawns, Black 3. Files fully open (no pawns of either colour): b, c, d, h — natural highways for the rooks and queen. Half-open for White: e, g.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
36. Bxg5 Kc7 37. Bf4+ Kb7 38. Qd7+ Kb6 39. Qb5#
Why it works
- Best move. bishop to g5 is exactly what the engine plays (#3).
- Spot on — bishop to f4 (#2).
- Precise: queen to d7 is the top choice (#1).
- Best move. queen to b5 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kc7, then Bf4+ and you stay on top.
Move by move
- 36. Bxg5 — bishop to g5 (capture)
- Kc7 — king to c7
- 37. Bf4+ — bishop to f4 with check
- Kb7 — king to b7
- 38. Qd7+ — queen to d7 with check
- Kb6 — king to b6
- 39. Qb5# — queen to b5 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.
Queen endgame
Queens on an open board — precision above all.
Queen endgames are treacherous: the queen reaches everywhere, and one slip turns a win into perpetual check. The signs are few pawns, exposed kings, and checks hanging in the air. Tuck your king away early, and use your own checks to bring the queen closer or push your passer with tempo. The typical mistake is grabbing pawns while leaving your king exposed to endless checks.
About this position
These pieces come from starting position #84.
SP-84 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
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 b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionScout family; read right to left it becomes position 878.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #84Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-84
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