Mate in 3: queen to d7 (e7·2)
c9-18567naming 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 1820 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 c1, queen e7, rook e2 c7, pawn b2 c2 g3 a4 h4 d5.
Black: king a6, queen a8, bishop g6, knight f7, pawn g4 a5 f5 b6 d6 h7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 40.
The position in numbers
White are ahead by 4 points of material (25 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on a6.
It is White to move on move 40, with 37 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): e — natural highways for the rooks and queen. Half-open for White: f.
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
40. Qd7 Qb7 41. Rxb7 Ne5 42. Ra7#
Why it works
- Great move! queen to d7 keeps the pressure (#2).
- Spot on — rook to b7 (#1).
- Precise: rook to a7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Qb7, then Rxb7 and you win the queen.
Move by move
- 40. Qd7 — queen to d7
- Qb7 — queen to b7
- 41. Rxb7 — rook to b7 (capture)
- Ne5 — knight to e5
- 42. Ra7# — rook to a7 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.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #935.
SP-935 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and d1, the queen on f1.
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 18.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 0 of 100 — class D — largest edge. Engine evaluation of the starting position: +78 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 60.0% (95% CI 46.2–72.4%).
Explore position #935Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-935
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