Mate in 3: bishop to b5 (f1·3)
c9-10801naming 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 3: a forced sequence that ends in checkmate.
Difficulty 1980 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 c1, rook g1 a8, bishop f1 b6, knight e4 c5, pawn a2 c2 f2 g2 h2 b3.
Black: king c8, rook g8, bishop f8, knight b8, pawn b5 f5 g7 h7.
13 white and 8 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 13 points of material (28 against 15; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on c8.
It is White to move on move 20, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
20. Bxb5 Bxc5 21. Nxc5 f4 22. Ba6#
Why it works
- Great move! bishop to b5 keeps the pressure (#2).
- Well found: knight to c5 (#1).
- Precise: bishop to a6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bxc5, then Nxc5 and you stay on top.
Move by move
- 20. Bxb5 — bishop to b5 (capture)
- Bxc5 — bishop to c5 (capture)
- 21. Nxc5 — knight to c5 (capture)
- f4 — pawn to f4
- 22. Ba6# — bishop to a6 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 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
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 #586.
SP-586 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on d1, the rooks on b1 and g1, the queen on a1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 277.
The engine's main line opens with b4.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 40, 400 000 000 nodes).
Explore position #586Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-586
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