Chess960 tactic on a5 (d2)
c9-12931naming 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 b1, queen d2, rook a8, bishop c2 h2, knight g3, pawn b2 h3 a4 c4.
Black: king b6, queen f3, bishop g8, knight g5 h8, pawn d3 a5 c5 f6 b7 h7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 3 points of material (27 against 24; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b6.
It is White to move on move 23, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 6. Files fully open (no pawns of either colour): e, g — natural highways for the rooks and queen. Half-open for White: d, f.
White hold the bishop pair, an edge in open lines. The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
23. Qxa5+ Kc6 24. Rc8+ Kd6 25. Qc7+ Ke6 26. Re8#
Why it works
- Best move. queen to a5 is exactly what the engine plays (#3).
- Spot on — rook to c8 (#2).
- Precise: queen to c7 is the top choice (#1).
- Best move. rook to e8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kc6, then Rc8+ and you stay on top.
Move by move
- 23. Qxa5+ — queen to a5 (capture) with check
- Kc6 — king to c6
- 24. Rc8+ — rook to c8 with check
- Kd6 — king to d6
- 25. Qc7+ — queen to c7 with check
- Ke6 — king to e6
- 26. Re8# — rook to e8 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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
About this position
These pieces come from starting position #925.
SP-925 · RampartScout — A wing-file king (b or g) and at least one corner knight: the rarest of the six families, just 72 positions.
The king starts on b1, the rooks on a1 and c1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the RampartScout family; read right to left it becomes position 40.
The engine's main line opens with a4.
Morozov Balance Index: 43 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +28 centipawns for White (depth 49, 400 000 000 nodes).
Explore position #925Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-925
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