Mate in 3: queen to d8 (d4·2)
c9-24159naming 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 a3, queen d4, rook c1, knight e2 e5, pawn b3 a4 b4.
Black: king b8, queen e6, rook g6, pawn g5 h5 b6.
8 white and 6 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
White are ahead by 6 points of material (23 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a3, the black king on b8.
It is White to move on move 38, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 3. Files fully open (no pawns of either colour): c, d, e, f — natural highways for the rooks and queen. Half-open for White: g, h.
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
38. Qd8+ Kb7 39. Rc7+ Ka6 40. Qa8#
Why it works
- Best move. queen to d8 is exactly what the engine plays (#2).
- Spot on — rook to c7 (#1).
- Precise: queen to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kb7, then Rc7+ and you stay on top.
Move by move
- 38. Qd8+ — queen to d8 with check
- Kb7 — king to b7
- 39. Rc7+ — rook to c7 with check
- Ka6 — king to a6
- 40. Qa8# — queen to a8 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.
About this position
These pieces come from starting position #811.
SP-811 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on b1, the rooks on a1 and f1, the queen on c1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartGuard family; read right to left it becomes position 145.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #811Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-811
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