Mate in 3: knight to d6 (f5·3)
c9-15341naming 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 1990 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 e1, rook f1 d5, bishop a1 c2, knight e2 f5, pawn a2 h2 c4 h4.
Black: king f8, rook a8, bishop c7, pawn a4 c5 d7 h7.
11 white and 7 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 14 points of material (26 against 12; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on f8.
It is White to move on move 25, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): b, e, f, g — natural highways for the rooks and queen. Half-open for White: d.
White hold the bishop pair, an edge in open lines. 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
25. Nd6+ Ke7 26. Rf7+ Kd8 27. Bf6#
Why it works
- Great move! knight to d6 keeps the pressure (#2).
- Spot on — rook to f7 (#1).
- Precise: bishop to f6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ke7, then Rf7+ and you stay on top.
Move by move
- 25. Nd6+ — knight to d6 with check
- Ke7 — king to e7
- 26. Rf7+ — rook to f7 with check
- Kd8 — king to d8
- 27. Bf6# — bishop to f6 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.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
About this position
These pieces come from starting position #640.
SP-640 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on e1, the rooks on c1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on d2, e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 223.
The engine's main line opens with c4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #640Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-640
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