Winning blow: rook to e7 (h7·4)
c9-28511naming 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 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.
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 e1, queen g8, rook g3 h7, bishop c1, pawn c3 d3 c4 e5 e6.
Black: king c8, queen d8, pawn a4 c5 f5 b7 e7.
10 white and 7 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 13 points of material (27 against 14; 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 c8.
It is White to move on move 33, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): g, h — natural highways for the rooks and queen. Half-open for White: a, b, f.
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
33. Rxe7 a3 34. Qxd8+ Kxd8 35. Rd7+ Ke8 36. Rg8#
Why it works
- Best move. rook to e7 is exactly what the engine plays (#3).
- Spot on — queen to d8 (#2).
- Precise: rook to d7 is the top choice (#1).
- Best move. rook to g8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead a3, then Qxd8+ and you win the queen.
Move by move
- 33. Rxe7 — rook to e7 (capture)
- a3 — pawn to a3
- 34. Qxd8+ — queen to d8 (capture) with check
- Kxd8 — king to d8 (capture)
- 35. Rd7+ — rook to d7 with check
- Ke8 — king to e8
- 36. Rg8# — rook to g8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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.
Simplification
Trade the heavy pieces and steer into a won endgame.
Simplification is how you convert an advantage: by trading queens and rooks you extinguish the counterplay and steer the game into a won endgame. The rule is simple — the side with extra material trades pieces but keeps pawns. Look for exchanges once the material is already won and your opponent is still rattling threats. The mistake is avoiding the queen trade and letting him muddy the water forever.
About this position
These pieces come from starting position #340.
SP-340 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on e1, the rooks on d1 and g1, the queen on f1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 334.
The engine's main line opens with c4.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #340Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-340
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