Chess960 tactic on d6 (d1·4)
c9-13425naming 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 f1, queen e1, rook d1 g2, bishop c5, knight b2, pawn a3 b3 f3 c4 h4.
Black: king d7, rook g8, bishop c3 a8, knight d6, pawn a5 h5 c6.
11 white and 8 black pieces are on the board; the puzzle position arises after move 28.
The position in numbers
White are ahead by 13 points of material (30 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on d7.
It is White to move on move 28, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): d, e, g — natural highways for the rooks and queen.
Black 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
28. Rxd6+ Kc8 29. Rxg8+ Kb7 30. Qe7+ Ka6 31. Rxa8#
Why it works
- Best move. rook to d6 is exactly what the engine plays (#3).
- Spot on — rook to g8 (#2).
- Precise: queen to e7 is the top choice (#1).
- Best move. rook to a8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kc8, then Rxg8+ and you win the rook.
Move by move
- 28. Rxd6+ — rook to d6 (capture) with check
- Kc8 — king to c8
- 29. Rxg8+ — rook to g8 (capture) with check
- Kb7 — king to b7
- 30. Qe7+ — queen to e7 with check
- Ka6 — king to a6
- 31. Rxa8# — rook to a8 (capture) 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.
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 #448.
SP-448 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on f1, the rooks on c1 and h1, the queen on g1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 703.
The engine's main line opens with c4.
Morozov Balance Index: 75 of 100 — class A — most balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #448Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-448
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