Mate in 3: queen to a8 (g2·2)
c9-26264naming 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 h2, queen g2, rook f1 f5, pawn h3 a4 c4 e5 g6.
Black: king g8, queen h4, rook e6, knight f6, pawn b6 h6 a7 g7.
9 white and 8 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 3 points of material (24 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on h2, the black king on g8.
It is White to move on move 37, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): d, f — natural highways for the rooks and queen. Half-open for White: b.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. Qa8+ Re8 38. Qxe8+ Nxe8 39. Rf8#
Why it works
- Great move! queen to a8 keeps the pressure (#2).
- Well found: queen to e8 (#1).
- Strong! rook to f8 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Re8, then Qxe8+ and you win the rook.
Move by move
- 37. Qa8+ — queen to a8 with check
- Re8 — rook to e8
- 38. Qxe8+ — queen to e8 (capture) with check
- Nxe8 — knight to e8 (capture)
- 39. Rf8# — rook to f8 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.
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 #109.
SP-109 · 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 a1.
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 d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 856.
The engine's main line opens with h3.
Morozov Balance Index: 94 of 100 — class A — most balanced. Engine evaluation of the starting position: +10 centipawns for White (depth 49, 400 000 000 nodes).
Explore position #109Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-109
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