Mate in 3: knight to g5 (f3)
c9-26502naming 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 f1, queen d8, rook b1 h1, knight f3, pawn c2 e2 f2 g2 a5 h6.
Black: king f7, rook d6 a8, bishop b8, pawn b2 e4 f5 a6 b7 d7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 8 points of material (28 against 20; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f7.
It is White to move on move 23, with 39 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: b, d.
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
23. Ng5+ Kg6 24. Qg8+ Kf6 25. Qg7#
Why it works
- Great move! knight to g5 keeps the pressure (#2).
- Spot on — queen to g8 (#1).
- Strong! queen to g7 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Kg6, then Qg8+ and you stay on top.
Move by move
- 23. Ng5+ — knight to g5 with check
- Kg6 — king to g6
- 24. Qg8+ — queen to g8 with check
- Kf6 — king to f6
- 25. Qg7# — queen to g7 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
About this position
These pieces come from starting position #504.
SP-504 · BastionGuard — King off-centre on c or f with both knights on inner files.
The king starts on f1, the rooks on a1 and h1, 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.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 557.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 8 of 100 — class D — largest edge. Engine evaluation of the starting position: +45 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #504Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-504
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