Mate in 2: queen to b8 (e8)
c9-26856naming 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 1220 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 b2, queen e8, rook f1 c7, bishop e1, knight h1, pawn a2 d2 g2 h2 a3 e3 f4.
Black: king b6, rook d6, pawn a5 b5 e5 f6 d7.
13 white and 7 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 22 points of material (32 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 b2, the black king on b6.
It is White to move on move 21, with 48 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 5. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen. Half-open for White: b.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Qb8+ Ka6 22. Qb7#
Why it works
- Best move. queen to b8 is exactly what the engine plays (#1).
- Spot on — queen to b7 (#).
- The line ends in a forced mate in 2.
- If instead Ka6, then Qb7# and it is mate.
Move by move
- 21. Qb8+ — queen to b8 with check
- Ka6 — king to a6
- 22. Qb7# — queen to b7 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 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.
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 #794.
SP-794 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins in a corner.
The king starts on c1, the rooks on a1 and g1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 165.
The engine's main line opens with e3.
Morozov Balance Index: 0 of 100 — class D — largest edge. Engine evaluation of the starting position: +67 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 62.0% (95% CI 48.2–74.1%).
Explore position #794Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-794
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