Mate in 3: rook to g8 (e8·4)
c9-17901naming 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 1990 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 g3, rook b7 a8 e8, pawn f3 h4 g5.
Black: king g7, rook a4, bishop b3, knight f4, pawn g6 f7.
7 white and 6 black pieces are on the board; the puzzle position arises after move 42.
The position in numbers
White are ahead by 5 points of material (18 against 13; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g3, the black king on g7.
It is White to move on move 42, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 2. Files fully open (no pawns of either colour): a, b, c, d, e — 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
42. Rg8+ Kh7 43. Rh8+ Kg7 44. Rag8#
Why it works
- Best move. rook to g8 is exactly what the engine plays (#2).
- Spot on — rook to h8 (#1).
- Precise: rook to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kh7, then Rh8+ and you stay on top.
Move by move
- 42. Rg8+ — rook to g8 with check
- Kh7 — king to h7
- 43. Rh8+ — rook to h8 with check
- Kg7 — king to g7
- 44. Rag8# — rook to g8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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.
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
About this position
These pieces come from starting position #393.
SP-393 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on g1, the rooks on b1 and h1, the queen on a1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 761.
The engine's main line opens with h4.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #393Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-393
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