Chess960 tactic on d4 (e3·3)
c9-16829naming 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 2250 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 g1, queen e3, rook b1, bishop e4, knight a6, pawn a2 c2 d2 g2 h2 f4.
Black: king a7, rook h8, bishop f7, knight b6, pawn a4 c4 d4 e7 g7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 9 points of material (26 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 g1, the black king on a7.
It is White to move on move 23, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: e.
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. Qxd4 Rb8 24. Nxb8 Kxb8 25. Qd8+ Ka7 26. Qxb6#
Why it works
- Best move. queen to d4 is exactly what the engine plays (#3).
- Spot on — knight to b8 (#2).
- Precise: queen to d8 is the top choice (#1).
- Best move. queen to b6 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Rb8, then Nxb8 and you win the rook.
Move by move
- 23. Qxd4 — queen to d4 (capture)
- Rb8 — rook to b8
- 24. Nxb8 — knight to b8 (capture)
- Kxb8 — king to b8 (capture)
- 25. Qd8+ — queen to d8 with check
- Ka7 — king to a7
- 26. Qxb6# — queen to b6 (capture) 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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #749.
SP-749 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and h1, the queen on f1.
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: d2.
The setup belongs to the RampartGuard family; read right to left it becomes position 408.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 4 of 100 — class D — largest edge. Engine evaluation of the starting position: +50 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #749Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-749
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