Mate in 2: rook to b8 (b1·3)
c9-24506naming 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 1320 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 a2, rook b1, knight e3 c6, pawn c2 e2 f2 h2 a5 d5.
Black: king c8, queen c3, rook h7, knight f8, pawn g3 e4 h4 d6 g6 a7 c7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
Black are ahead by 7 points of material (17 against 24; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a2, the black king on c8.
It is White to move on move 26, with 33 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: g.
The White king has 0 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
26. Rb8+ Kd7 27. Rd8#
Why it works
- Great move! rook to b8 keeps the pressure (#1).
- Well found: rook to d8 (#).
- The line ends in a forced mate in 2.
- If instead Kd7, then Rd8# and it is mate.
Move by move
- 26. Rb8+ — rook to b8 with check
- Kd7 — king to d7
- 27. Rd8# — rook to d8 and it is checkmate
Types in this puzzle
Hook mate
Rook, knight and pawn form a hook the king cannot escape.
The hook mate is a three-piece construction: the rook mates, the knight guards the rook, and a pawn guards the knight. The rook strikes the king at close range along a line, the knight stands diagonally nearby stealing the escape squares, and the pawn anchors the chain. The pattern usually appears near the edge after a rook invasion. Build it link by link — first plant the knight under pawn protection, then crash in with the rook.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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.
About this position
These pieces come from starting position #531.
SP-531 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on b1 and g1, the queen on e1.
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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneGuard family; read right to left it becomes position 515.
The engine's main line opens with b3.
Morozov Balance Index: 81 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 centipawns for White (depth 47, 400 000 000 nodes).
In 50 self-play games White scored 54.0% (95% CI 40.4–67.0%).
Explore position #531Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-531
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