Attack on the uncastled king: knight to e7 (f5·17)
c9-08245naming 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 2: the first move creates an unstoppable threat, the second delivers mate.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1670 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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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 g1, queen d1, rook e1 f2, bishop c1, knight c5 f5, pawn a2 g2 h2 c3 e5.
Black: king f8, queen d8, rook e8 h8, bishop c7 c8, knight a8, pawn b5 d5 h5 e6 a7 g7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 1 points of material (33 against 34; 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 f8.
It is White to move on move 16, with 54 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: b, d.
Black hold the bishop pair, an edge in open lines. 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
16. Ne7+ Kxe7 17. Bg5#
Why it works
- Great move! knight to e7 keeps the pressure (#1).
- Well found: bishop to g5 (#).
- The line ends in a forced mate in 2.
- If instead Kxe7, then Bg5# and it is mate.
Move by move
- 16. Ne7+ — knight to e7 with check
- Kxe7 — king to e7 (capture)
- 17. Bg5# — bishop to g5 and it is checkmate
Types in this puzzle
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
Sacrifice attack
Give up material to unleash a decisive attack.
A sacrificial attack gives up material on purpose to rip the king's shelter open and launch a decisive assault. The sac is sound when you get concrete assets in return: open lines to the king, tempi, pieces ready to pour in. The signs: a poorly sheltered king, your forces aimed at its home, defenders stranded far away. The iron rule is to calculate, not hope — once the material is gone, there is no way back.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #308.
SP-308 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins in a corner.
The king starts on f1, the rooks on e1 and g1, the queen on d1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 366.
The engine's main line opens with O-O, bringing the king out to g1.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #308Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 013 · SP-308
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