Mate in 3: knight to b5 (d6)
c9-25425naming 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 c1, queen g2, rook a1 d8, bishop d1 e1, knight d6, pawn b2 c2 e3 g4 h4 a5.
Black: king a7, rook a8, bishop h5, knight c6, pawn b5 e5 e6 h6 b7 c7 g7.
13 white and 11 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 16 points of material (34 against 18; 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 a7.
It is White to move on move 23, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. Files fully open (no pawns of either colour): d, f — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. 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
23. Nxb5+ Ka6 24. Nxc7+ Ka7 25. Rxa8#
Why it works
- Great move! knight to b5 keeps the pressure (#2).
- Spot on — knight to c7 (#1).
- Precise: rook to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ka6, then Nxc7+ and you stay on top.
Move by move
- 23. Nxb5+ — knight to b5 (capture) with check
- Ka6 — king to a6
- 24. Nxc7+ — knight to c7 (capture) with check
- Ka7 — king to a7
- 25. Rxa8# — rook to a8 (capture) 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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #553.
SP-553 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on c1, the rooks on a1 and h1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 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 505.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 72 of 100 — class B — balanced. Engine evaluation of the starting position: +20 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #553Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-553
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