Mate in 3: pawn to b5 (b4·2)
c9-11448naming 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 2170 ShuffleRating — expert level — few solve it at first try.
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 a2, queen f6, bishop c3, pawn d2 d3 b4.
Black: king d5, bishop f8, knight h2, pawn h5 b6.
6 white and 5 black pieces are on the board; the puzzle position arises after move 35.
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 a2, the black king on d5.
It is White to move on move 35, with 32 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 2. Files fully open (no pawns of either colour): a, c, e, f, g — natural highways for the rooks and queen. Half-open for White: h.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
35. b5 Bd6 36. Qf5+ Be5 37. Qxe5#
Why it works
- Sensible development: pawn to b5.
- Spot on — queen to f5 (#1).
- Precise: queen to e5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bd6, then Qf5+ and you stay on top.
Move by move
- 35. b5 — pawn to b5
- Bd6 — bishop to d6
- 36. Qf5+ — queen to f5 with check
- Be5 — bishop to e5
- 37. Qxe5# — queen to e5 (capture) 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 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 #833.
SP-833 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on c1, the rooks on b1 and f1, the queen on g1.
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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 123.
The engine's main line opens with f4.
Morozov Balance Index: 92 of 100 — class A — most balanced. Engine evaluation of the starting position: +12 centipawns for White (depth 49, 400 000 000 nodes).
Explore position #833Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-833
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