Winning blow: rook to c8 (c6·3)
c9-12157naming 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 in 4: a forced checkmate in four moves — every reply is covered.
Winning tactic: there is a move that gains a decisive advantage — find it.
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.
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.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 c2, rook c6, bishop e1, knight d4, pawn g2 f4 h4.
Black: king b8, queen g7, knight d5, pawn b4 f5 h5 d6 e6 g6.
8 white and 9 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
White are ahead by 5 points of material (23 against 18; 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 b8.
It is White to move on move 36, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 6. Files fully open (no pawns of either colour): a, c — natural highways for the rooks and queen. Half-open for White: b, d, e.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
36. Rc8+ Ka7 37. Qa4+ Kb6 38. Qc6+ Ka5 39. Qb5#
Why it works
- Great move! rook to c8 keeps the pressure (#3).
- Well found: queen to a4 (#2).
- Precise: queen to c6 is the top choice (#1).
- Best move. queen to b5 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Ka7, then Qa4+ and you stay on top.
Move by move
- 36. Rc8+ — rook to c8 with check
- Ka7 — king to a7
- 37. Qa4+ — queen to a4 with check
- Kb6 — king to b6
- 38. Qc6+ — queen to c6 with check
- Ka5 — king to a5
- 39. Qb5# — queen to b5 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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #842.
SP-842 · RampartScout — The king starts on b or g while a knight begins on the a- or h-file — the smallest family.
The king starts on b1, the rooks on a1 and d1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 117.
The engine's main line opens with a4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #842Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-842
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