Mate in 3: queen to b5 (b4)
c9-11317naming 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 1760 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 f1, queen b4, rook c1, bishop a1 g4, knight e1 g2, pawn a2 d3 c4 f6.
Black: king e8, rook c7 g8, pawn d4 b5 a7 f7 g7 h7.
11 white and 9 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 14 points of material (30 against 16; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on e8.
It is White to move on move 24, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 6. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: b, g, h.
White hold the bishop pair, an edge in open lines. 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
24. Qxb5+ Rc6 25. Qxc6+ Kd8 26. Qc8#
Why it works
- Best move. queen to b5 is exactly what the engine plays (#2).
- Spot on — queen to c6 (#1).
- Precise: queen to c8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rc6, then Qxc6+ and you win the rook.
Move by move
- 24. Qxb5+ — queen to b5 (capture) with check
- Rc6 — rook to c6
- 25. Qxc6+ — queen to c6 (capture) with check
- Kd8 — king to d8
- 26. Qc8# — queen to c8 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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #481.
SP-481 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on f1, the rooks on c1 and h1, the queen on b1.
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.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 571.
The engine's main line opens with c4.
Morozov Balance Index: 99 of 100 — class A — most balanced. Engine evaluation of the starting position: +5 centipawns for White (depth 48, 400 000 000 nodes).
In 50 self-play games White scored 51.0% (95% CI 37.6–64.3%).
Explore position #481Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-481
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads