Mate in 3: knight to a6
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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 b2, queen g1, rook d1, bishop f1, knight b4 c5, pawn c2 g2 h2 f3 c4 b6.
Black: king b8, queen g8, rook d3, bishop e8 f8, knight c8, pawn e5 f6 g7 h7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
White are ahead by 2 points of material (29 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on b8.
It is White to move on move 19, with 37 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): a, d — natural highways for the rooks and queen. Half-open for White: e.
Black hold the bishop pair, an edge in open lines. The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
19. Nba6+ Ka8 20. b7+ Ka7 21. b8=Q#
Why it works
- Great move! knight to a6 keeps the pressure (#2).
- Spot on — pawn to b7 (#1).
- Precise: pawn to b8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ka8, then b7+ and you stay on top.
Move by move
- 19. Nba6+ — knight to a6 with check
- Ka8 — king to a8
- 20. b7+ — pawn to b7 with check
- Ka7 — king to a7
- 21. b8=Q# — pawn to b8 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.
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 #842.
SP-842 · RampartScout — The king starts on b or g while a knight begins on the a- or h-file — the smallest family.
The king starts on b1, the rooks on a1 and d1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 117.
The engine's main line opens with a4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #842Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-842
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