Chess960 tactic on c6 (e4)
c9-09978naming 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 2250 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 b2, queen a7, rook b1 f1, bishop e4, knight a5 g5, pawn a2 c2 h2 g3 b4 f4.
Black: king e8, queen d2, rook b8 f8, bishop c8, knight e2, pawn c4 f5 d6 g6 e7 h7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
White are ahead by 3 points of material (34 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on e8.
It is White to move on move 18, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d, e.
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
18. Bc6+ Kd8 19. Ne6+ Bxe6 20. Qxb8+ Bc8 21. Qb6#
Why it works
- Great move! bishop to c6 keeps the pressure (#3).
- Well found: knight to e6 (#2).
- Strong! queen to b8 is the sharp choice (#1).
- Best move. queen to b6 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kd8, then Ne6+ and you stay on top.
Move by move
- 18. Bc6+ — bishop to c6 with check
- Kd8 — king to d8
- 19. Ne6+ — knight to e6 with check
- Bxe6 — bishop to e6 (capture)
- 20. Qxb8+ — queen to b8 (capture) with check
- Bc8 — bishop to c8
- 21. Qb6# — queen to b6 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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
About this position
These pieces come from starting position #279.
SP-279 · ThroneScout — Centre-file king, rim knight: 204 of the 960 positions share this pattern.
The king starts on d1, the rooks on b1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
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: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 578.
The engine's main line opens with f4.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +51 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #279Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-279
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads