Mate in 3: rook to a3
c9-11321Opens 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 1630 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 e2, queen e8, rook c3, bishop d3, pawn f2 h2 e3 f3.
Black: king a7, rook b7, pawn h3 c5 d5 f7 g7.
8 white and 7 black pieces are on the board; the puzzle position arises after move 32.
The position in numbers
White are ahead by 11 points of material (21 against 10; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e2, the black king on a7.
It is White to move on move 32, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 5. Files fully open (no pawns of either colour): a, b — natural highways for the rooks and queen. Half-open for White: c, d, g.
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
32. Ra3+ Kb6 33. Ra6+ Kc7 34. Rc6#
Why it works
- Best move. rook to a3 is exactly what the engine plays (#2).
- Spot on — rook to a6 (#1).
- Precise: rook to c6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kb6, then Ra6+ and you stay on top.
Move by move
- 32. Ra3+ — rook to a3 with check
- Kb6 — king to b6
- 33. Ra6+ — rook to a6 with check
- Kc7 — king to c7
- 34. Rc6# — rook to c6 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.
About this position
These pieces come from starting position #250.
SP-250 · 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 c1, the rooks on b1 and h1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 613.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 18 of 100 — class D — largest edge. Engine evaluation of the starting position: +38 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #250Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-250
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