Mate in 3: queen to a5 (d2·3)
c9-28439naming 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 d1, queen d2, rook c1 g3, bishop h1 c5, knight f1, pawn h2 a4 f4 b5.
Black: king d8, rook f8, bishop a1 e8, pawn e4 g4 f5 g6 d7.
11 white and 9 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
White are ahead by 16 points of material (32 against 16; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on d8.
It is White to move on move 27, with 54 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): c — natural highways for the rooks and queen. Half-open for White: d, e, 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
27. Qa5+ Kc8 28. Qa8+ Kc7 29. b6#
Why it works
- Best move. queen to a5 is exactly what the engine plays (#2).
- Spot on — queen to a8 (#1).
- Precise: pawn to b6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kc8, then Qa8+ and you stay on top.
Move by move
- 27. Qa5+ — queen to a5 with check
- Kc8 — king to c8
- 28. Qa8+ — queen to a8 with check
- Kc7 — king to c7
- 29. b6# — pawn to b6 and it is checkmate
Types in this puzzle
Pawn mate
The humblest soldier delivers the final blow.
The pawn mate lets the humblest soldier land the final blow. It happens to a king stuck among its own and enemy pieces: the pawn strikes diagonally from one square away and there is nowhere left to run. The sign: the squares around the king are covered or occupied, and your pawn stands one step from striking distance. Never write pawns out of your attack — their blows are the cheapest and therefore the most humiliating.
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 #219.
SP-219 · ThroneScout — Centre-file king, rim knight: 204 of the 960 positions share this pattern.
The king starts on d1, the rooks on c1 and g1, the queen on b1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 641.
The engine's main line opens with c3.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #219Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-219
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