Mate in 2: rook to c3 (c1)
c9-16755naming 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 2: the first move creates an unstoppable threat, the second delivers mate.
Difficulty 1220 ShuffleRating — club-player level.
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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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 d3, queen d5, rook c1, bishop a5, knight b1 f7, pawn f2 a4.
Black: king c8, queen c3, rook h2 b8, pawn b4 a6.
8 white and 6 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 4 points of material (25 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d3, the black king on c8.
It is White to move on move 37, with 4 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 2 pawns, Black 2. Files fully open (no pawns of either colour): c, d, e, g, h — 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
37. Rxc3+ bxc3 38. Qc6#
Why it works
- Best move. rook to c3 is exactly what the engine plays (#1).
- Spot on — queen to c6 (#).
- The line ends in a forced mate in 2.
- If instead bxc3, then Qc6# and it is mate.
Move by move
- 37. Rxc3+ — rook to c3 (capture) with check
- bxc3 — pawn to c3 (capture)
- 38. Qc6# — queen to c6 and it is checkmate
Types in this puzzle
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
Decoy
A sacrifice lures the king or a piece onto a fatal square.
A decoy is the mirror image of deflection: you sacrifice to drag the king or a piece onto a fatal square. The classic is a queen or rook sac whose capture pulls the king into a knight fork, a discovered check or mate. Find the square where the target will be hit, then find the offer it cannot refuse. Calculate to the very end — a decoy only works when the follow-up is forced.
About this position
These pieces come from starting position #635.
SP-635 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on a1 and f1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
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 225.
The engine's main line opens with g4.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #635Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-635
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