Mate in 3: rook to d7 (d1·5)
c9-26244naming 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 g2, queen g5, rook d1 f1, bishop a2, knight h3, pawn h2 f3 b4.
Black: king g7, rook e8, bishop b8, knight g6, pawn h4 f5 b6 a7 c7 d7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 11 points of material (28 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g2, the black king on g7.
It is White to move on move 21, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 6. Files fully open (no pawns of either colour): e, g — natural highways for the rooks and queen. Half-open for White: a, c, d.
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
21. Rxd7+ Re7 22. Rxe7+ Kh8 23. Qf6#
Why it works
- Best move. rook to d7 is exactly what the engine plays (#2).
- Spot on — rook to e7 (#1).
- Precise: queen to f6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Re7, then Rxe7+ and you win the rook.
Move by move
- 21. Rxd7+ — rook to d7 (capture) with check
- Re7 — rook to e7
- 22. Rxe7+ — rook to e7 (capture) with check
- Kh8 — king to h8
- 23. Qf6# — queen to f6 and it is checkmate
Types in this puzzle
Corner mate
Driven into the corner, the king runs out of squares.
The corner mate catches a king driven into the corner, where it has only three neighboring squares — all of them taken away or blocked. The corner is the worst home for a king, because the attacker needs to control the fewest squares there. Herd the king toward the corner with checks and never let it slip back toward the center. Cut off the escape routes before the final check, and the mate practically assembles itself.
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.
About this position
These pieces come from starting position #160.
SP-160 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on f1, the rooks on d1 and h1, the queen on g1.
The queenside rook already stands on d1, so castling long moves only the king, from f1 to c1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 799.
The engine's main line opens with f3.
Morozov Balance Index: 9 of 100 — class D — largest edge. Engine evaluation of the starting position: +44 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #160Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-160
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