Chess960 tactic on c5 (c4·2)
c9-28540naming 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 c4, rook g7, knight c3, pawn e2 b4 d4 e5.
Black: king a6, rook g1, pawn d5 g5.
7 white and 4 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 5 points of material (12 against 7; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c4, the black king on a6.
It is White to move on move 37, with 5 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 4 pawns, Black 2. Files fully open (no pawns of either colour): a, c, f, h — natural highways for the rooks and queen. Half-open for White: g.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. Kc5 Rb1 38. Nxb1 g4 39. b5+ Ka5 40. Ra7#
Why it works
- Great move! king to c5 keeps the pressure (#3).
- Spot on — knight to b1 (#2).
- Precise: pawn to b5 is the top choice (#1).
- Best move. rook to a7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Rb1, then Nxb1 and you win the rook.
Move by move
- 37. Kc5 — king to c5
- Rb1 — rook to b1
- 38. Nxb1 — knight to b1 (capture)
- g4 — pawn to g4
- 39. b5+ — pawn to b5 with check
- Ka5 — king to a5
- 40. Ra7# — rook to a7 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.
Passed pawn
Nothing can stop the passer — escort it to the last rank.
A passed pawn has no enemy pawns in front of it or on the neighboring files: only pieces can stop it. Check who can blockade the pawn or catch it with the king — if nobody can, the pawn is worth a whole piece. Push the passer with your pieces supporting it, and put your rook behind it. The beginner's mistake is shoving the pawn forward unprotected, straight into a capture.
Breakthrough
A pawn sacrifice tears the chain open and lets a passer through.
A breakthrough is a pawn sacrifice that rips the opponent's chain open and creates an unstoppable passer. Look for it where the pawns are locked against each other: often two pawns are given up so the third one slips through. Check the square rule — can the enemy king catch the new passer? If not, sacrifice with confidence; the classic error is breaking through while his king stands right there eating everything.
About this position
These pieces come from starting position #867.
SP-867 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on c1 and e1, the queen on b1.
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 a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 83.
The engine's main line opens with b4.
Morozov Balance Index: 78 of 100 — class A — most balanced. Engine evaluation of the starting position: +18 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #867Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-867
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