Mate in 3: queen to a8 (c6)
c9-19990naming 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 h1, queen c6, rook f1 e6, bishop f2, knight f5, pawn g2 h2 b3 f3 a4 e4.
Black: king f8, rook b6 h8, bishop f7, pawn a5 b5 f6 h6 c7 g7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 12 points of material (31 against 19; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on h1, the black king on f8.
It is White to move on move 25, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: c.
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
25. Qa8+ Rb8 26. Qxb8+ Be8 27. Qxe8#
Why it works
- Best move. queen to a8 is exactly what the engine plays (#2).
- Spot on — queen to b8 (#1).
- Precise: queen to e8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rb8, then Qxb8+ and you win the rook.
Move by move
- 25. Qa8+ — queen to a8 with check
- Rb8 — rook to b8
- 26. Qxb8+ — queen to b8 (capture) with check
- Be8 — bishop to e8
- 27. Qxe8# — queen to e8 (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.
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 #414.
SP-414 · ThroneGuard — King on a central file (d/e) with both knights on inner files — the classic-type setup.
The king starts on e1, the rooks on a1 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.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneGuard family; read right to left it becomes position 740.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 50, 400 000 000 nodes).
Explore position #414Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-414
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