Mate in 3: pawn to d6 (d5)
c9-25824naming 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 1760 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 d1, queen h8, rook g1, knight e4 f6, pawn a2 c2 e2 f2 b4 d5.
Black: king e7, queen h4, rook d8, bishop h6, knight f8, pawn b6 e6 g6 a7 c7 d7 h7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
Black are ahead by 1 points of material (26 against 27; 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 e7.
It is White to move on move 19, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. 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
19. d6+ cxd6 20. Ng8+ Kf7 21. Nxd6#
Why it works
- Great move! pawn to d6 keeps the pressure (#2).
- Well found: knight to g8 (#1).
- Strong! knight to d6 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead cxd6, then Ng8+ and you stay on top.
Move by move
- 19. d6+ — pawn to d6 with check
- cxd6 — pawn to d6 (capture)
- 20. Ng8+ — knight to g8 with check
- Kf7 — king to f7
- 21. Nxd6# — knight to d6 (capture) 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.
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.
Zwischenzug
Before the obvious recapture — an in-between move that wins more.
A zwischenzug means refusing the obvious reply — usually a recapture — and playing a stronger move with tempo first. Typically it is a check or a deadly threat the opponent must answer, after which you calmly take what was hanging anyway. The sign: inside a sequence of exchanges you own a check or a threat that will not run away. Whenever a line looks forced, ask what poison you can slip in between the moves.
About this position
These pieces come from starting position #691.
SP-691 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on b1 and g1, the queen on c1.
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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 451.
The engine's main line opens with g3.
Morozov Balance Index: 72 of 100 — class B — balanced. Engine evaluation of the starting position: +20 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #691Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-691
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