Winning blow: bishop to f6 (a1·18)
c9-09092naming 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 2350 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 e1, queen h6, rook c4, bishop a1 h1, knight d1 f2, pawn a2 c2 d2 e3 g5.
Black: king e7, rook g8, knight g6, pawn a7 d7 f7 h7.
12 white and 7 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
White are ahead by 19 points of material (31 against 12; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e7.
It is White to move on move 22, with 48 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: 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
22. Bf6+ Ke6 23. Qh3+ Kd6 24. Ne4+ Kd5 25. Rc5#
Why it works
- Best move. bishop to f6 is exactly what the engine plays (#3).
- Spot on — queen to h3 (#2).
- Precise: knight to e4 is the top choice (#1).
- Best move. rook to c5 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Ke6, then Qh3+ and you stay on top.
Move by move
- 22. Bf6+ — bishop to f6 with check
- Ke6 — king to e6
- 23. Qh3+ — queen to h3 with check
- Kd6 — king to d6
- 24. Ne4+ — knight to e4 with check
- Kd5 — king to d5
- 25. Rc5# — rook to c5 and it is checkmate
Types in this puzzle
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.
About this position
These pieces come from starting position #435.
SP-435 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on f1, the rooks on b1 and g1, the queen on e1.
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.
The second rank carries 2 pawns with no defender at all: c2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 707.
The engine's main line opens with b3.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #435Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-435
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