Winning blow: knight to b6 (c4·18)
c9-16838naming 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 4: a forced checkmate in four moves — every reply is covered.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 2120 ShuffleRating — expert level — few solve it at first try.
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.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 b1, queen b5, rook e1, knight c4 d5, pawn d2 e6.
Black: king b8, rook b6 f8, bishop e7, pawn g3 a7.
7 white and 6 black pieces are on the board; the puzzle position arises after move 34.
The position in numbers
White are ahead by 7 points of material (22 against 15; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 34, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 2 pawns, Black 2. Files fully open (no pawns of either colour): b, c, f, h — natural highways for the rooks and queen. Half-open for White: a, g.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
34. Ncxb6 Bd6 35. Nc4+ Ka8 36. Nxd6 Rb8 37. Nc7#
Why it works
- Best move. knight to b6 is exactly what the engine plays (#3).
- Spot on — knight to c4 (#2).
- Precise: knight to d6 is the top choice (#1).
- Best move. knight to c7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Bd6, then Nc4+ and you win the rook.
Move by move
- 34. Ncxb6 — knight to b6 (capture)
- Bd6 — bishop to d6
- 35. Nc4+ — knight to c4 with check
- Ka8 — king to a8
- 36. Nxd6 — knight to d6 (capture)
- Rb8 — rook to b8
- 37. Nc7# — knight to c7 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 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
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 #895.
SP-895 · 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 d1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 64.
The engine's main line opens with g4.
Morozov Balance Index: 11 of 100 — class D — largest edge. Engine evaluation of the starting position: +42 centipawns for White (depth 41, 400 000 000 nodes).
Explore position #895Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-895
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