Mate in 2: knight to b5
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The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate in 2: the first move creates an unstoppable threat, the second delivers mate.
Difficulty 1090 ShuffleRating — club-player level.
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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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 f8, bishop h1, knight c3, pawn b2 c2 h2 a4 c6.
Black: king a7, rook e7, bishop g4, knight c5, pawn a5 b6 c7 h7.
9 white and 8 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 1 points of material (16 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 a7.
It is White to move on move 25, with 31 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): d, e, f, g — 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
25. Nb5+ Ka6 26. Ra8#
Why it works
- Great move! knight to b5 keeps the pressure (#1).
- Spot on — rook to a8 (#).
- The line ends in a forced mate in 2.
- If instead Ka6, then Ra8# and it is mate.
Move by move
- 25. Nb5+ — knight to b5 with check
- Ka6 — king to a6
- 26. Ra8# — rook to a8 and it is checkmate
Types in this puzzle
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
Endgame tactic
Tactics live in the endgame too — strike while material is scarce.
Tactics do not retire when the queens come off: forks, pins and double attacks live on in the endgame. With so little material left, every tactical loss is almost always decisive. The signs are the usual ones — undefended pieces, king and piece on one line, a pawn about to promote. Even in a "technical" ending, scan for a shot before every move, both yours and your opponent's.
About this position
These pieces come from starting position #823.
SP-823 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on b1, the rooks on a1 and f1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
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: h2.
The setup belongs to the RampartGuard family; read right to left it becomes position 130.
The engine's main line opens with a4.
Morozov Balance Index: 100 of 100 — class A — most balanced. Engine evaluation of the starting position: -5 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 52.0% (95% CI 38.5–65.2%).
Explore position #823Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-823
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