Mate in 3: rook to c8 (c6)
c9-18125naming 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.
A fork made possible by the Chess960 piece placement.
Difficulty 1860 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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 a1, queen d1, rook c1 c6, bishop f1 g3, knight f3, pawn b2 h2 a4 d7.
Black: king a8, queen f8, rook d8, bishop e4, knight f6 h8, pawn f2 a7 b7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 5 points of material (32 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a1, the black king on a8.
It is White to move on move 24, with 52 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, e, g — natural highways for the rooks and queen. Half-open for White: f.
White hold the bishop pair, an edge in open lines. The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Rc8+ Rxc8 25. Rxc8+ Qxc8 26. dxc8=Q#
Why it works
- Great move! rook to c8 keeps the pressure (#2).
- Spot on — rook to c8 (#1).
- Precise: pawn to c8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rxc8, then Rxc8+ and you stay on top.
Move by move
- 24. Rc8+ — rook to c8 with check
- Rxc8 — rook to c8 (capture)
- 25. Rxc8+ — rook to c8 (capture) with check
- Qxc8 — queen to c8 (capture)
- 26. dxc8=Q# — pawn to c8 (capture) and it is checkmate
Types in this puzzle
Back-rank mate
The king is locked behind its own pawns — a heavy piece strikes the last rank.
The back-rank mate strikes a king locked behind its own unmoved pawns when a rook or queen crashes onto the last rank. The signs: no escape hole in front of the king, and the back rank guarded by a single piece or by nobody at all. Often that lone guard is deflected or traded off first, and only then comes the invasion. In your own games, make luft in time — one pawn move prevents a sudden catastrophe.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
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 #922.
SP-922 · RampartScout — A knight in the corner and the king out on the wing (b/g); like every family, it is closed under mirror twins.
The king starts on b1, the rooks on a1 and c1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartScout family; read right to left it becomes position 37.
The engine's main line opens with c4.
Morozov Balance Index: 97 of 100 — class A — most balanced. Engine evaluation of the starting position: +7 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #922Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-922
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