Mate in 3: rook to g8 (g5)
c9-27139naming 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 c1, queen f5, rook g5, bishop b1 c3, knight b2, pawn a2 d2 e4 h4.
Black: king e8, queen b5, bishop f4 b7, knight c8, pawn e5 b6 a7 d7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
White are ahead by 5 points of material (27 against 22; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on e8.
It is White to move on move 27, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): c, f, g — 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
27. Rg8+ Ke7 28. Qf8+ Ke6 29. Rg6#
Why it works
- Great move! rook to g8 keeps the pressure (#2).
- Spot on — queen to f8 (#1).
- Strong! rook to g6 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Ke7, then Qf8+ and you stay on top.
Move by move
- 27. Rg8+ — rook to g8 with check
- Ke7 — king to e7
- 28. Qf8+ — queen to f8 with check
- Ke6 — king to e6
- 29. Rg6# — rook to g6 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.
About this position
These pieces come from starting position #80.
SP-80 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on f1, the rooks on e1 and g1, the queen on h1.
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.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 879.
The engine's main line opens with g4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +83 centipawns for White (depth 43, 400 000 000 nodes).
In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
Explore position #80Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-80
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