Mate in 3: rook to f7 (f1·4)
c9-18184naming 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 1860 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 f8, rook f1, bishop b1 g3, knight b3 a5, pawn a2 b2 d2 h2 c3 e4.
Black: king d7, queen h6, rook c8, bishop e6 b8, knight a6 b6, pawn d4 c5 h5 a7 g7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 1 points of material (32 against 31; 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 d7.
It is White to move on move 20, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: g.
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
20. Rf7+ Bxf7 21. Qxf7+ Kd8 22. Nb7#
Why it works
- Great move! rook to f7 keeps the pressure (#2).
- Well found: queen to f7 (#1).
- Precise: knight to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bxf7, then Qxf7+ and you stay on top.
Move by move
- 20. Rf7+ — rook to f7 with check
- Bxf7 — bishop to f7 (capture)
- 21. Qxf7+ — queen to f7 (capture) with check
- Kd8 — king to d8
- 22. Nb7# — knight to b7 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.
Sacrifice attack
Give up material to unleash a decisive attack.
A sacrificial attack gives up material on purpose to rip the king's shelter open and launch a decisive assault. The sac is sound when you get concrete assets in return: open lines to the king, tempi, pieces ready to pour in. The signs: a poorly sheltered king, your forces aimed at its home, defenders stranded far away. The iron rule is to calculate, not hope — once the material is gone, there is no way back.
About this position
These pieces come from starting position #92.
SP-92 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on d1 and f1, the queen on h1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 876.
The engine's main line opens with f4.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #92Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-92
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