Chess960 tactic on c5 (a5)
c9-16789naming 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 e1, queen a5, rook d1 g1, bishop a4, knight c3, pawn a2 b2 e2 f2 c4 h4 g5.
Black: king e5, queen h7, rook g8, bishop e4 d8, pawn c5 h5 e6 f6 g7.
13 white and 10 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 7 points of material (32 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e5.
It is White to move on move 20, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 5. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen.
Black hold the bishop pair, an edge in open lines. 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
20. Qxc5+ Bd5 21. Rxd5+ exd5 22. Qxd5+ Kf4 23. e3#
Why it works
- Great move! queen to c5 keeps the pressure (#3).
- Spot on — rook to d5 (#2).
- Precise: queen to d5 is the top choice (#1).
- Best move. pawn to e3 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Bd5, then Rxd5+ and you win the bishop.
Move by move
- 20. Qxc5+ — queen to c5 (capture) with check
- Bd5 — bishop to d5
- 21. Rxd5+ — rook to d5 (capture) with check
- exd5 — pawn to d5 (capture)
- 22. Qxd5+ — queen to d5 (capture) with check
- Kf4 — king to f4
- 23. e3# — pawn to e3 and it is checkmate
Types in this puzzle
Pawn mate
The humblest soldier delivers the final blow.
The pawn mate lets the humblest soldier land the final blow. It happens to a king stuck among its own and enemy pieces: the pawn strikes diagonally from one square away and there is nowhere left to run. The sign: the squares around the king are covered or occupied, and your pawn stands one step from striking distance. Never write pawns out of your attack — their blows are the cheapest and therefore the most humiliating.
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.
About this position
These pieces come from starting position #473.
SP-473 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on f1, the rooks on a1 and g1, the queen on h1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the BastionGuard family; read right to left it becomes position 681.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 7 of 100 — class D — largest edge. Engine evaluation of the starting position: +47 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #473Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-473
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