Mate in 3: king to b2 (b3)
c9-16547naming 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 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 b3, queen f7, knight b5, pawn c3 a4 h4.
Black: king b8, rook b2, pawn e4 a5 b7.
6 white and 5 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
White are ahead by 7 points of material (15 against 8; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b3, the black king on b8.
It is White to move on move 36, with 3 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 3 pawns, Black 3. Files fully open (no pawns of either colour): d, f, g — natural highways for the rooks and queen. Half-open for White: b, e.
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
36. Kxb2 b6 37. Qc7+ Ka8 38. Qc8#
Why it works
- Best move. king to b2 is exactly what the engine plays (#2).
- Spot on — queen to c7 (#1).
- Precise: queen to c8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead b6, then Qc7+ and you win the rook.
Move by move
- 36. Kxb2 — king to b2 (capture)
- b6 — pawn to b6
- 37. Qc7+ — queen to c7 with check
- Ka8 — king to a8
- 38. Qc8# — queen to c8 and it is checkmate
Types in this puzzle
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.
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.
Queen endgame
Queens on an open board — precision above all.
Queen endgames are treacherous: the queen reaches everywhere, and one slip turns a win into perpetual check. The signs are few pawns, exposed kings, and checks hanging in the air. Tuck your king away early, and use your own checks to bring the queen closer or push your passer with tempo. The typical mistake is grabbing pawns while leaving your king exposed to endless checks.
About this position
These pieces come from starting position #701.
SP-701 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on a1 and h1, 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 d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 456.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 75 of 100 — class B — balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #701Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-701
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