Mate in 3: rook to c6 (c1)
c9-12700naming 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 a2, rook c1 c7, bishop b5, pawn b2 g2 f3 a4 h4.
Black: king b6, rook e1 e3, pawn f4 g6.
9 white and 5 black pieces are on the board; the puzzle position arises after move 40.
The position in numbers
White are ahead by 6 points of material (18 against 12; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a2, the black king on b6.
It is White to move on move 40, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 2. Files fully open (no pawns of either colour): c, d, e — natural highways for the rooks and queen.
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
40. R1c6+ Ka5 41. Ra6+ Kb4 42. Rc4#
Why it works
- Best move. rook to c6 is exactly what the engine plays (#2).
- Spot on — rook to a6 (#1).
- Strong! rook to c4 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Ka5, then Ra6+ and you stay on top.
Move by move
- 40. R1c6+ — rook to c6 with check
- Ka5 — king to a5
- 41. Ra6+ — rook to a6 with check
- Kb4 — king to b4
- 42. Rc4# — rook to c4 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.
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.
Endgame tactic
Tactics live in the endgame too — strike while material is scarce.
Tactics do not retire when the queens come off: forks, pins and double attacks live on in the endgame. With so little material left, every tactical loss is almost always decisive. The signs are the usual ones — undefended pieces, king and piece on one line, a pawn about to promote. Even in a "technical" ending, scan for a shot before every move, both yours and your opponent's.
About this position
These pieces come from starting position #506.
SP-506 · ThroneGuard — The king starts in the middle of the back rank, on d or e, and neither knight begins in a corner.
The king starts on d1, the rooks on a1 and h1, the queen on b1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 549.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #506Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-506
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