Mate in 3: queen to b7 (a7·2)
c9-27604naming 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 c1, queen a7, rook g1 c2, bishop h4, knight b6 d6, pawn a2 b2 d2 c3 g4.
Black: king d8, queen f3, rook c8 e8, bishop h8, knight e6, pawn h5 c6 b7 d7 e7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 3 points of material (33 against 30; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on d8.
It is White to move on move 24, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: e, h.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Qxb7 Rc7 25. Qb8+ Rc8 26. Qxc8#
Why it works
- Best move. queen to b7 is exactly what the engine plays (#2).
- Spot on — queen to b8 (#1).
- Precise: queen to c8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rc7, then Qb8+ and you stay on top.
Move by move
- 24. Qxb7 — queen to b7 (capture)
- Rc7 — rook to c7
- 25. Qb8+ — queen to b8 with check
- Rc8 — rook to c8
- 26. Qxc8# — queen to c8 (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.
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 #219.
SP-219 · ThroneScout — Centre-file king, rim knight: 204 of the 960 positions share this pattern.
The king starts on d1, the rooks on c1 and g1, the queen on b1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 641.
The engine's main line opens with c3.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #219Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-219
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