Mate in 3: queen to a7 (g1)
c9-22469naming 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 e1, queen g1, rook b1 h1, bishop a1 a6, knight d2 g3, pawn g2 a3 e4 h4 c6.
Black: king c8, queen g8, rook d8 h8, bishop f4 b7, knight h6, pawn e6 f6 a7 c7 g7 h7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 2 points of material (36 against 34; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on c8.
It is White to move on move 21, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): b, d — natural highways for the rooks and queen. Half-open for White: f.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Qxa7 Bxg3+ 22. Kf1 Rxd2 23. Qa8#
Why it works
- Great move! queen to a7 keeps the pressure (#2).
- Well found: king to f1 (#1).
- Precise: queen to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bxg3+, then Kf1 and you stay on top.
Move by move
- 21. Qxa7 — queen to a7 (capture)
- Bxg3+ — bishop to g3 (capture) with check
- 22. Kf1 — king to f1
- Rxd2 — rook to d2 (capture)
- 23. Qa8# — queen to a8 and it is checkmate
Types in this puzzle
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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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 #66.
SP-66 · 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 d1 and h1, the queen on g1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
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: c2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 887.
The engine's main line opens with b3.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #66Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-66
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads