Mate in 3: knight to d8 (e6)
c9-28407naming 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 g1, rook c1 b7, knight e6, pawn h2.
Black: king g8, rook d8, pawn e5 f6.
5 white and 4 black pieces are on the board; the puzzle position arises after move 40.
The position in numbers
White are ahead by 7 points of material (14 against 7; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 40, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 1 pawns, Black 2. Files fully open (no pawns of either colour): a, b, c, d, g — natural highways for the rooks and queen. Half-open for White: e, f.
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
40. Nxd8 f5 41. Rc8 Kh8 42. Ne6#
Why it works
- Best move. knight to d8 is exactly what the engine plays (#2).
- rook to c8 develops smoothly.
- Precise: knight to e6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead f5, then Rc8 and you win the rook.
Move by move
- 40. Nxd8 — knight to d8 (capture)
- f5 — pawn to f5
- 41. Rc8 — rook to c8
- Kh8 — king to h8
- 42. Ne6# — knight to e6 and it is checkmate
Types in this puzzle
Discovered mate
A piece steps aside — and the one behind it delivers mate.
In a discovered mate the piece that moves is not the one that mates — the long-range piece behind it delivers the blow. The moving piece is completely free: it can land anywhere, ideally stealing the king's last squares or guarding key points. Look for your rook, bishop or queen lined up with the enemy king, with exactly one of your own pieces in between. When choosing the unveiling move, remember its second job — shutting the king's escape door.
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.
Endgame tactic
Tactics live in the endgame too — strike while material is scarce.
Tactics do not retire when the queens come off: forks, pins and double attacks live on in the endgame. With so little material left, every tactical loss is almost always decisive. The signs are the usual ones — undefended pieces, king and piece on one line, a pawn about to promote. Even in a "technical" ending, scan for a shot before every move, both yours and your opponent's.
About this position
These pieces come from starting position #490.
SP-490 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on d1, the rooks on b1 and h1, the queen on a1.
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 e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneGuard family; read right to left it becomes position 565.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #490Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-490
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