Mate in 3: knight to b7
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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 b1, rook c6, bishop g3, knight d6, pawn a2 b2 h4 d5 g5 e6.
Black: king a5, bishop f2, knight a4, pawn b5 h5 g6 a7.
10 white and 7 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 7 points of material (17 against 10; 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 a5.
It is White to move on move 37, with 28 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): c, f — natural highways for the rooks and queen.
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
37. Nb7+ Kb4 38. a3+ Kb3 39. Na5#
Why it works
- Best move. knight to b7 is exactly what the engine plays (#2).
- Spot on — pawn to a3 (#1).
- Precise: knight to a5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kb4, then a3+ and you stay on top.
Move by move
- 37. Nb7+ — knight to b7 with check
- Kb4 — king to b4
- 38. a3+ — pawn to a3 with check
- Kb3 — king to b3
- 39. Na5# — knight to a5 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.
Breakthrough
A pawn sacrifice tears the chain open and lets a passer through.
A breakthrough is a pawn sacrifice that rips the opponent's chain open and creates an unstoppable passer. Look for it where the pawns are locked against each other: often two pawns are given up so the third one slips through. Check the square rule — can the enemy king catch the new passer? If not, sacrifice with confidence; the classic error is breaking through while his king stands right there eating everything.
About this position
These pieces come from starting position #566.
SP-566 · ThroneGuard — The king starts in the middle of the back rank, on d or e, and neither knight begins in a corner.
The king starts on d1, the rooks on a1 and g1, the queen on h1.
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 c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 486.
The engine's main line opens with h4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #566Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-566
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