Attack on the uncastled king: bishop to f6 (e7)
c9-22339naming 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 in 3: a forced sequence that ends in checkmate.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1630 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
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 e1, queen e6, rook b1 h1, bishop g2 e7, pawn e2 h2 g3 a4 b4 f4.
Black: king e8, queen b8, rook h6 a8, knight a5, pawn f5 h5 a6 c7.
12 white and 9 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
White are ahead by 5 points of material (31 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e8.
It is White to move on move 27, with 53 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: c.
White hold the bishop pair, an edge in open lines. The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
27. Bf6+ Kf8 28. Qe7+ Kg8 29. Bd5#
Why it works
- Great move! bishop to f6 keeps the pressure (#2).
- Well found: queen to e7 (#1).
- Precise: bishop to d5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kf8, then Qe7+ and you stay on top.
Move by move
- 27. Bf6+ — bishop to f6 with check
- Kf8 — king to f8
- 28. Qe7+ — queen to e7 with check
- Kg8 — king to g8
- 29. Bd5# — bishop to d5 and it is checkmate
Types in this puzzle
Two-bishop mate
The bishop pair sweeps two adjacent diagonals — the king has nowhere to hide.
The two-bishop mate rakes two adjacent diagonals: one bishop mates while the other seals off the escape squares. The bishops complement each other perfectly — living on opposite colors, together they cover an unbroken strip of the board. The pattern usually appears at the edge or in the corner where the king was pressed beforehand. Treasure the bishop pair until the attack comes — on an open board two adjacent diagonals become a solid wall.
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
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 #430.
SP-430 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on e1, the rooks on a1 and h1, the queen on c1.
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 f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 724.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 16 of 100 — class D — largest edge. Engine evaluation of the starting position: +39 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #430Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-430
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