Chess960 tactic on c6 (d5·3)
c9-14638naming 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 c1, queen e6, rook b1 h1, bishop f1, pawn c2 d2 g2 h2 b3 d5.
Black: king d8, queen a2, bishop f8, knight c6, pawn a3 e5 h5 g6 c7.
11 white and 9 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 8 points of material (28 against 20; 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 d8.
It is White to move on move 23, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: a, e.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
23. dxc6 Qb2+ 24. Rxb2 axb2+ 25. Kb1 e4 26. Qd7#
Why it works
- Great move! pawn to c6 keeps the pressure (#3).
- Well found: rook to b2 (#2).
- A natural move: king to b1.
- Best move. queen to d7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Qb2+, then Rxb2 and you win the queen.
Move by move
- 23. dxc6 — pawn to c6 (capture)
- Qb2+ — queen to b2 with check
- 24. Rxb2 — rook to b2 (capture)
- axb2+ — pawn to b2 (capture) with check
- 25. Kb1 — king to b1
- e4 — pawn to e4
- 26. Qd7# — queen to d7 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
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 #170.
SP-170 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on b1 and h1, the queen on g1.
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 e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneScout family; read right to left it becomes position 789.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #170Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-170
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