Mate in 3: pawn to b6 (a5·2)
c9-28313naming 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 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 d2, rook a3 g7, bishop d1, pawn c2 f2 d3 b4 e4 a5.
Black: king d8, rook h1, pawn d4 f4 b6 d6.
10 white and 6 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
White are ahead by 10 points of material (19 against 9; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d2, the black king on d8.
It is White to move on move 30, with 32 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): g, h — natural highways for the rooks and queen.
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
30. axb6 Rxd1+ 31. Kxd1 f3 32. Ra8#
Why it works
- Best move. pawn to b6 is exactly what the engine plays (#2).
- Spot on — king to d1 (#1).
- Precise: rook to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rxd1+, then Kxd1 and you win the rook.
Move by move
- 30. axb6 — pawn to b6 (capture)
- Rxd1+ — rook to d1 (capture) with check
- 31. Kxd1 — king to d1 (capture)
- f3 — pawn to f3
- 32. Ra8# — rook to a8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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.
Endgame tactic
Tactics live in the endgame too — strike while material is scarce.
Tactics do not retire when the queens come off: forks, pins and double attacks live on in the endgame. With so little material left, every tactical loss is almost always decisive. The signs are the usual ones — undefended pieces, king and piece on one line, a pawn about to promote. Even in a "technical" ending, scan for a shot before every move, both yours and your opponent's.
About this position
These pieces come from starting position #661.
SP-661 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on e1, the rooks on a1 and f1, the queen on h1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 202.
The engine's main line opens with Nc3, bringing the knight out to c3.
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 #661Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-661
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