Mate in 3: queen to d3 (f3)
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The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate in 3: a forced sequence that ends in checkmate.
A fork made possible by the Chess960 piece placement.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 f3, rook b1 f7, bishop d2, knight e2 b6, pawn a2 c2 g3 h3 b4 e4.
Black: king d8, queen c7, rook c4 e8, pawn a5 h6 b7 g7.
13 white and 8 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
White are ahead by 11 points of material (34 against 23; 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 26, with 54 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, f — 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
26. Qd3+ Rd4 27. Qxd4+ Qd6 28. Qxd6#
Why it works
- Best move. queen to d3 is exactly what the engine plays (#2).
- Spot on — queen to d4 (#1).
- Precise: queen to d6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rd4, then Qxd4+ and you win the rook.
Move by move
- 26. Qd3+ — queen to d3 with check
- Rd4 — rook to d4
- 27. Qxd4+ — queen to d4 (capture) with check
- Qd6 — queen to d6
- 28. Qxd6# — queen to d6 (capture) 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.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
About this position
These pieces come from starting position #373.
SP-373 · ThroneScout — A central king (d or e), but with a knight posted out on the a- or h-file.
The king starts on e1, the rooks on b1 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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 298.
The engine's main line opens with f4.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +51 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #373Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-373
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