Chess960 tactic on c6 (a6)
c9-10511naming 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 2350 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 c1, rook a6, bishop d5 f6, knight f4, pawn c2 d2 h2 b4 g5.
Black: king d6, knight c6, pawn b5 g6 h6.
10 white and 5 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 13 points of material (19 against 6; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on d6.
It is White to move on move 33, with 46 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): a, e, f — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
33. Rxc6+ Kd7 34. Ne6 Ke8 35. Nc5 Kf8 36. Rc8#
Why it works
- Best move. rook to c6 is exactly what the engine plays (#3).
- knight to e6 develops smoothly.
- A natural move: knight to c5.
- Best move. rook to c8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kd7, then Ne6 and you win the knight.
Move by move
- 33. Rxc6+ — rook to c6 (capture) with check
- Kd7 — king to d7
- 34. Ne6 — knight to e6
- Ke8 — king to e8
- 35. Nc5 — knight to c5
- Kf8 — king to f8
- 36. Rc8# — rook to c8 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.
About this position
These pieces come from starting position #819.
SP-819 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and f1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 131.
The engine's main line opens with b3.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #819Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-819
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