Mate in 3: knight to b6 (d5·2)
c9-21309naming 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 g1, queen c6, rook e1 f1, bishop b1 c1, knight h1 d5, pawn a2 e2 g3 h3 c4 f7.
Black: king f8, queen b6, rook e7 h8, pawn a7 g7 h7.
14 white and 7 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 15 points of material (37 against 22; 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 f8.
It is White to move on move 17, with 11 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 6 pawns, Black 3. Files fully open (no pawns of either colour): b, d — natural highways for the rooks and queen.
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
17. Nxb6 Rxf7 18. Qc8+ Ke7 19. Ba3#
Why it works
- Best move. knight to b6 is exactly what the engine plays (#2).
- Spot on — queen to c8 (#1).
- Precise: bishop to a3 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rxf7, then Qc8+ and you win the queen.
Move by move
- 17. Nxb6 — knight to b6 (capture)
- Rxf7 — rook to f7 (capture)
- 18. Qc8+ — queen to c8 with check
- Ke7 — king to e7
- 19. Ba3# — bishop to a3 and it is checkmate
Types in this puzzle
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #292.
SP-292 · BastionScout — A knight on the a- or h-file, king on c or f — the mirror twin lands here as well.
The king starts on f1, the rooks on e1 and g1, the queen on a1.
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.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 382.
The engine's main line opens with c4.
Morozov Balance Index: 19 of 100 — class D — largest edge. Engine evaluation of the starting position: +49 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 51.0% (95% CI 37.6–64.3%).
Explore position #292Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-292
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