Chess960 tactic on b7 (e4·4)
c9-13318naming 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 c1, queen e4, bishop a1, knight f2, pawn a2 c2 h2 g3.
Black: king d8, pawn b4 d6 g6 h7.
8 white and 5 black pieces are on the board; the puzzle position arises after move 28.
The position in numbers
White are ahead by 15 points of material (19 against 4; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on d8.
It is White to move on move 28, with 46 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): e, f — natural highways for the rooks and queen. Half-open for White: b, d.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
28. Qb7 Ke8 29. Bf6 Kf8 30. Qe7+ Kg8 31. Qg7#
Why it works
- Great move! queen to b7 keeps the pressure (#3).
- bishop to f6 develops smoothly.
- Precise: queen to e7 is the top choice (#1).
- Best move. queen to g7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Ke8, then Bf6 and you stay on top.
Move by move
- 28. Qb7 — queen to b7
- Ke8 — king to e8
- 29. Bf6 — bishop to f6
- Kf8 — king to f8
- 30. Qe7+ — queen to e7 with check
- Kg8 — king to g8
- 31. Qg7# — queen to g7 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.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #946.
SP-946 · 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 c1, the rooks on b1 and d1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 7.
The engine's main line opens with g3.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #946Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-946
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