Mate in 3: queen to b4 (c3)
c9-15331naming 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 2210 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 c3, rook b1, knight f5, pawn h2 a3 g3.
Black: king c5, queen f6, rook d8 g8, bishop d5, pawn a4 c4 g4 h5 f7.
7 white and 10 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
Black are ahead by 7 points of material (20 against 27; 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 c5.
It is White to move on move 37, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 5. Files fully open (no pawns of either colour): b, d, e — natural highways for the rooks and queen. Half-open for White: c, f.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. Qb4+ Kc6 38. Qb7+ Kc5 39. Qb5#
Why it works
- Best move. queen to b4 is exactly what the engine plays (#2).
- Spot on — queen to b7 (#1).
- Precise: queen to b5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kc6, then Qb7+ and you stay on top.
Move by move
- 37. Qb4+ — queen to b4 with check
- Kc6 — king to c6
- 38. Qb7+ — queen to b7 with check
- Kc5 — king to c5
- 39. Qb5# — queen to b5 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.
About this position
These pieces come from starting position #756.
SP-756 · ThroneGuard — King on a central file (d/e) with both knights on inner files — the classic-type setup.
The king starts on d1, the rooks on a1 and g1, the queen on h1.
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.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 398.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #756Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-756
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