Chess960 tactic on c6 (c8)
c9-09157naming 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 2400 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 d2, rook g1 c8, bishop b4, pawn a2 e2 h2 c3 c4 g6 h6.
Black: king a4, rook d7, pawn d6 a7 e7.
11 white and 5 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 12 points of material (20 against 8; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d2, the black king on a4.
It is White to move on move 29, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 3. Files fully open (no pawns of either colour): b, f — natural highways for the rooks and queen. Half-open for White: d.
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
29. Rc6 a5 30. Ra6 Ra7 31. Rxa7 d5 32. Rxa5#
Why it works
- Sensible development: rook to c6.
- rook to a6 develops smoothly.
- Precise: rook to a7 is the top choice (#1).
- Best move. rook to a5 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead a5, then Ra6 and you stay on top.
Move by move
- 29. Rc6 — rook to c6
- a5 — pawn to a5
- 30. Ra6 — rook to a6
- Ra7 — rook to a7
- 31. Rxa7 — rook to a7 (capture)
- d5 — pawn to d5
- 32. Rxa5# — rook to a5 (capture) and it is checkmate
Types in this puzzle
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.
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 #91.
SP-91 · ThroneScout — A central king (d or e), but with a knight posted out on the a- or h-file.
The king starts on d1, the rooks on c1 and f1, the queen on g1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The second rank carries 2 pawns with no defender at all: a2, b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 865.
The engine's main line opens with g4.
Morozov Balance Index: 26 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +34 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #91Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-91
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