Mate in 3: queen to d8 (e8·3)
c9-09488naming 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 2170 ShuffleRating — expert level — few solve it at first try.
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 e8, rook b1 e1, bishop e2 c3, knight a1 b5, pawn b2 c2 g2 e4.
Black: king c6, queen g7, bishop d7 f8, knight g8, pawn h2 f4 f6 b7 h7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
White are ahead by 12 points of material (35 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 c6.
It is White to move on move 19, with 42 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, d — natural highways for the rooks and queen. Half-open for White: f, h.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
19. Qd8 Bc8 20. Na7+ Kc5 21. Nb3#
Why it works
- Great move! queen to d8 keeps the pressure (#2).
- Spot on — knight to a7 (#1).
- Precise: knight to b3 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bc8, then Na7+ and you stay on top.
Move by move
- 19. Qd8 — queen to d8
- Bc8 — bishop to c8
- 20. Na7+ — knight to a7 with check
- Kc5 — king to c5
- 21. Nb3# — knight to b3 and it is checkmate
Types in this puzzle
Knight mate
The knight lands the killing blow from its unique angle.
In a knight mate the final blow comes from the knight — the only piece whose check can never be blocked. That makes it lethal against a cramped king: only a king move or capturing the knight itself can help. The sign: the squares around the king are occupied or covered, and there is a hop from which the knight checks while staying untouchable. Bring the knight over early — it is slower than the long-range pieces, but its strike cannot be parried.
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.
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 #374.
SP-374 · 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 e1, 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 294.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #374Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-374
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