Chess960 tactic on c5 (c1)
c9-12053naming 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: a forcing sequence that ends the game — the king has no escape.
Mate in 4: a forced checkmate in four moves — every reply is covered.
Difficulty 2120 ShuffleRating — expert level — few solve it at first try.
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.
This is a forced mating attack. Start from the enemy king: which of its squares are already covered, and which move takes away the rest while keeping the king in check? Forcing moves — checks and captures — are what turn an attack into mate.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
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 e2, rook c1 h7, bishop e3, knight a5, pawn d2 g2 h2 a3 b4.
Black: king c8, rook e4 e6, pawn a4 c5 g5.
10 white and 6 black pieces are on the board; the puzzle position arises after move 34.
The position in numbers
White are ahead by 8 points of material (21 against 13; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e2, the black king on c8.
It is White to move on move 34, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen. Half-open for White: c.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
34. Rxc5+ Rc6 35. Rxc6+ Kd8 36. Nb7+ Ke8 37. Rc8#
Why it works
- Great move! rook to c5 keeps the pressure (#3).
- Spot on — rook to c6 (#2).
- Precise: knight to b7 is the top choice (#1).
- Best move. rook to c8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Rc6, then Rxc6+ and you win the rook.
Move by move
- 34. Rxc5+ — rook to c5 (capture) with check
- Rc6 — rook to c6
- 35. Rxc6+ — rook to c6 (capture) with check
- Kd8 — king to d8
- 36. Nb7+ — knight to b7 with check
- Ke8 — king to e8
- 37. Rc8# — rook to c8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
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.
About this position
These pieces come from starting position #870.
SP-870 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on b1 and e1, the queen on a1.
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 c1 and f1; their long diagonals reach h6 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 ThroneScout family; read right to left it becomes position 86.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 10 of 100 — class D — largest edge. Engine evaluation of the starting position: +44 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 55.0% (95% CI 41.3–67.9%).
Explore position #870Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-870
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