Chess960 tactic on d7 (d6·4)
c9-11534naming 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 c2, rook h1 d6, bishop c5, knight e4 f6, pawn a2 b2 e2 f3 h4.
Black: king e7, queen a8, rook g2, bishop c4, knight g5, pawn b5 h5 a7.
12 white and 8 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 10 points of material (33 against 23; 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 e7.
It is White to move on move 21, with 51 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): c, d, g — 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
21. Rd7+ Ke6 22. Re7+ Kf5 23. Ng3+ Kxf6 24. Qf5#
Why it works
- Best move. rook to d7 is exactly what the engine plays (#3).
- Spot on — rook to e7 (#2).
- Precise: knight to g3 is the top choice (#1).
- Best move. queen to f5 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Ke6, then Re7+ and you stay on top.
Move by move
- 21. Rd7+ — rook to d7 with check
- Ke6 — king to e6
- 22. Re7+ — rook to e7 with check
- Kf5 — king to f5
- 23. Ng3+ — knight to g3 with check
- Kxf6 — king to f6 (capture)
- 24. Qf5# — queen to f5 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.
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.
About this position
These pieces come from starting position #12.
SP-12 · BastionGuard — King off-centre on c or f with both knights on inner files.
The king starts on f1, the rooks on e1 and h1, the queen on a1.
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.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
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 956.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #12Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-12
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