Mate in 3: queen to d7 (d5)
c9-25401naming 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 h2, queen d5, rook e1, knight b5, pawn b3 f3 g3 c4 f4 h4.
Black: king g7, queen b6, rook h6, knight f5, pawn b4 a5 c5 h5 f6 g6.
10 white and 10 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
Material is level — 23 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on h2, the black king on g7.
It is White to move on move 37, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen. Half-open for White: a.
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
37. Qd7+ Ne7 38. Rxe7+ Kg8 39. Re8#
Why it works
- Great move! queen to d7 keeps the pressure (#2).
- Spot on — rook to e7 (#1).
- Precise: rook to e8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ne7, then Rxe7+ and you win the knight.
Move by move
- 37. Qd7+ — queen to d7 with check
- Ne7 — knight to e7
- 38. Rxe7+ — rook to e7 (capture) with check
- Kg8 — king to g8
- 39. Re8# — rook to e8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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 #145.
SP-145 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on g1, the rooks on c1 and h1, the queen on f1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the RampartGuard family; read right to left it becomes position 811.
The engine's main line opens with e3.
Morozov Balance Index: 94 of 100 — class A — most balanced. Engine evaluation of the starting position: +10 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #145Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-145
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