Mate in 3: rook to a8 (e8)
c9-22275naming 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 f1, queen c1, rook g1 e8, bishop h1, knight f6, pawn e2 a3 b3 d3 f4 h4 g5.
Black: king g7, queen a8, bishop h8, pawn d4 e4 e6 g6 h6 f7.
13 white and 9 black pieces are on the board; the puzzle position arises after move 28.
The position in numbers
White are ahead by 14 points of material (32 against 18; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on g7.
It is White to move on move 28, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen.
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
28. Rxa8 hxg5 29. fxg5 e3 30. Rg8#
Why it works
- Best move. rook to a8 is exactly what the engine plays (#2).
- Spot on — pawn to g5 (#1).
- Precise: rook to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead hxg5, then fxg5 and you win the queen.
Move by move
- 28. Rxa8 — rook to a8 (capture)
- hxg5 — pawn to g5 (capture)
- 29. fxg5 — pawn to g5 (capture)
- e3 — pawn to e3
- 30. Rg8# — rook to g8 and it is checkmate
Types in this puzzle
Hook mate
Rook, knight and pawn form a hook the king cannot escape.
The hook mate is a three-piece construction: the rook mates, the knight guards the rook, and a pawn guards the knight. The rook strikes the king at close range along a line, the knight stands diagonally nearby stealing the escape squares, and the pawn anchors the chain. The pattern usually appears near the edge after a rook invasion. Build it link by link — first plant the knight under pawn protection, then crash in with the rook.
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.
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
About this position
These pieces come from starting position #107.
SP-107 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on f1, the rooks on c1 and g1, the queen on a1.
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 h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 849.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #107Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-107
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