Mate in 3: rook to g1 (f1·2)
c9-22983naming 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 f2, queen a1, rook f1, bishop f3, knight e2 e3, pawn a2 c2 b3 d3 e4 f4.
Black: king g8, queen d7, rook d8, bishop a8, pawn h4 b6 d6 a7 c7 e7 f7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
White are ahead by 4 points of material (29 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f2, the black king on g8.
It is White to move on move 18, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 8. Files fully open (no pawns of either colour): g — natural highways for the rooks and queen. Half-open for White: h.
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
18. Rg1+ Qg4 19. Rxg4+ Kf8 20. Qh8#
Why it works
- Great move! rook to g1 keeps the pressure (#2).
- Well found: rook to g4 (#1).
- Strong! queen to h8 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Qg4, then Rxg4+ and you win the queen.
Move by move
- 18. Rg1+ — rook to g1 with check
- Qg4 — queen to g4
- 19. Rxg4+ — rook to g4 (capture) with check
- Kf8 — king to f8
- 20. Qh8# — queen to h8 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.
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 #19.
SP-19 · 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 e1 and g1, the queen on c1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 931.
The engine's main line opens with g3.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #19Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-19
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