Mate in 3: queen to d8 (a5·2)
c9-24996naming 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.
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 a1, queen a5, rook c1 g3, bishop h1, pawn a2 b2 d4 g4.
Black: king b8, queen h7, rook f6 a8, bishop d1, knight e8, pawn g5 c6 b7 f7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
Black are ahead by 3 points of material (26 against 29; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a1, the black king on b8.
It is White to move on move 30, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): e, h — natural highways for the rooks and queen. Half-open for White: c, f.
The White king has 0 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. Qd8+ Ka7 31. Ra3+ Ba4 32. Rxa4#
Why it works
- Great move! queen to d8 keeps the pressure (#2).
- Spot on — rook to a3 (#1).
- Precise: rook to a4 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ka7, then Ra3+ and you stay on top.
Move by move
- 30. Qd8+ — queen to d8 with check
- Ka7 — king to a7
- 31. Ra3+ — rook to a3 with check
- Ba4 — bishop to a4
- 32. Rxa4# — rook to a4 (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 #278.
SP-278 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on b1 and g1, the queen on h1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the ThroneScout family; read right to left it becomes position 582.
The engine's main line opens with Nb3, bringing the knight out to b3.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #278Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-278
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads