Winning blow: knight to g5 (e4·15)
c9-14698naming 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 g1, queen c4, rook e1 f1, bishop f2, knight e4, pawn a2 g2 h3 a4.
Black: king h8, rook e8, bishop f8, pawn h4 a7 g7.
10 white and 6 black pieces are on the board; the puzzle position arises after move 35.
The position in numbers
White are ahead by 18 points of material (29 against 11; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on h8.
It is White to move on move 35, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): b, c, d, e, f — natural highways for the rooks and queen.
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
35. Ng5 Re6 36. Rxe6 Ba3 37. Qc8+ Bf8 38. Qxf8#
Why it works
- Sensible development: knight to g5.
- Spot on — rook to e6 (#2).
- Precise: queen to c8 is the top choice (#1).
- Best move. queen to f8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Re6, then Rxe6 and you win the rook.
Move by move
- 35. Ng5 — knight to g5
- Re6 — rook to e6
- 36. Rxe6 — rook to e6 (capture)
- Ba3 — bishop to a3
- 37. Qc8+ — queen to c8 with check
- Bf8 — bishop to f8
- 38. Qxf8# — queen to f8 (capture) and it is checkmate
Types in this puzzle
Corner mate
Driven into the corner, the king runs out of squares.
The corner mate catches a king driven into the corner, where it has only three neighboring squares — all of them taken away or blocked. The corner is the worst home for a king, because the attacker needs to control the fewest squares there. Herd the king toward the corner with checks and never let it slip back toward the center. Cut off the escape routes before the final check, and the mate practically assembles itself.
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #42.
SP-42 · RampartScout — King on the wing (b/g) with a knight on the rim (a/h) — the rarest family.
The king starts on g1, the rooks on d1 and h1, the queen on c1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the RampartScout family; read right to left it becomes position 917.
The engine's main line opens with c4.
Morozov Balance Index: 42 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +23 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
Explore position #42Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-42
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