Chess960 tactic on a7 (g7)
c9-16307naming 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 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.
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 b2, queen e2, rook g7, bishop d4, knight f3, pawn a2 c3 h3 f4.
Black: king a8, queen c6, pawn b5 f5 h5 e6.
9 white and 6 black pieces are on the board; the puzzle position arises after move 31.
The position in numbers
White are ahead by 11 points of material (24 against 13; 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 a8.
It is White to move on move 31, with 54 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): d, g — natural highways for the rooks and queen. Half-open for White: b, e.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
31. Ra7+ Kb8 32. Qe5+ Qd6 33. Qxd6+ Kc8 34. Qc7#
Why it works
- Best move. rook to a7 is exactly what the engine plays (#3).
- Spot on — queen to e5 (#2).
- Precise: queen to d6 is the top choice (#1).
- Best move. queen to c7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kb8, then Qe5+ and you stay on top.
Move by move
- 31. Ra7+ — rook to a7 with check
- Kb8 — king to b8
- 32. Qe5+ — queen to e5 with check
- Qd6 — queen to d6
- 33. Qxd6+ — queen to d6 (capture) with check
- Kc8 — king to c8
- 34. Qc7# — queen to c7 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.
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 #188.
SP-188 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on c1 and f1, the queen on h1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
The pawn on d2, e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 780.
The engine's main line opens with f4.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #188Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-188
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