Mate in 3: queen to a7 (a6·2)
c9-22542naming 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 1860 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 d1, queen a6, rook f1, bishop d3, knight a2 c2, pawn d2 e2 h2 g3 a4 f4 b6.
Black: king b8, queen c6, rook d8 e8, knight e4, pawn e5 f5 g6 h7.
13 white and 9 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
White are ahead by 4 points of material (30 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on b8.
It is White to move on move 26, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 4. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen.
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
26. Qa7+ Kc8 27. Ba6+ Qb7 28. Qxb7#
Why it works
- Great move! queen to a7 keeps the pressure (#2).
- Well found: bishop to a6 (#1).
- Precise: queen to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kc8, then Ba6+ and you stay on top.
Move by move
- 26. Qa7+ — queen to a7 with check
- Kc8 — king to c8
- 27. Ba6+ — bishop to a6 with check
- Qb7 — queen to b7
- 28. Qxb7# — queen to b7 (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 #563.
SP-563 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
The king starts on d1, the rooks on b1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 483.
The engine's main line opens with b3.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #563Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-563
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