Mate in 2: queen to b5 (f1)
c9-16305naming 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 2: the first move creates an unstoppable threat, the second delivers mate.
Difficulty 1440 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 c1, queen f1, rook e3, bishop a1, pawn a2 d2 h2.
Black: king b7, rook g2, pawn f5 g6 c7 d7.
7 white and 6 black pieces are on the board; the puzzle position arises after move 31.
The position in numbers
White are ahead by 11 points of material (20 against 9; 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 b7.
It is White to move on move 31, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 4. Files fully open (no pawns of either colour): b, e — natural highways for the rooks and queen. Half-open for White: c, f, g.
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
31. Qb5+ Ka8 32. Ra3#
Why it works
- Best move. queen to b5 is exactly what the engine plays (#1).
- Spot on — rook to a3 (#).
- The line ends in a forced mate in 2.
- If instead Ka8, then Ra3# and it is mate.
Move by move
- 31. Qb5+ — queen to b5 with check
- Ka8 — king to a8
- 32. Ra3# — rook to a3 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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.
Corner mate
Driven into the corner, the king runs out of squares.
The corner mate catches a king driven into the corner, where it has only three neighboring squares — all of them taken away or blocked. The corner is the worst home for a king, because the attacker needs to control the fewest squares there. Herd the king toward the corner with checks and never let it slip back toward the center. Cut off the escape routes before the final check, and the mate practically assembles itself.
About this position
These pieces come from starting position #945.
SP-945 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and e1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 11.
The engine's main line opens with f4.
Morozov Balance Index: 9 of 100 — class D — largest edge. Engine evaluation of the starting position: +44 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #945Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-945
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