Puzzle zwxp4_M — ELO 1817
This is a Black-to-move puzzle rated 1817 ELO. The first move is h4f6, tagged with 10 interpretable concepts and Lichess themes: crushing, defensiveMove, endgame.
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Position
Black to move. ELO 1817. Themes: crushing, defensiveMove, endgame, hangingPiece, veryLong.
FEN: 8/8/5P2/4K3/pk1N3b/8/1P6/8 b - - 0 43
Show solution (10 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: h4f6 e5f6 b4c4 f6e5 c4d3 e5d5 d3d2 d5c4 d2c1 c4c3
Concepts that fire on this position
Our SAE pipeline tagged this position with 10 active features. Each links to a page documenting that pattern in detail.
Why this puzzle is hard
The rarest pattern firing here is King under direct attack with no defensive pieces nearby, across various…, which appears in only 19 of our 9,950 puzzles (0.19%). Rare patterns tend to be the bottleneck — players who haven't internalised them will fail this puzzle even when their tactical calculation is otherwise solid.
The puzzle's Lichess ELO of 1817 reflects this: solvers below that rating typically miss the cue entirely.
Similar puzzles
Puzzles sharing the most concept tags with this one — a stronger signal than theme overlap because it reflects the actual patterns Leela recognises.
Train this pattern
Click through to the Climbchess trainer to attempt the position interactively against the same Leela network that tagged it. The trainer adapts difficulty using your live concept-recognition profile — it surfaces puzzles tagged with concepts you've been missing, not random brawls.
If you want the underlying methodology, the how-it-works page walks through the SAE training run, the labelling pipeline, and the puzzle-tagging procedure end-to-end.
Frequently asked
What is the rating of this puzzle?
1817 Lichess ELO. Solvers below that rating typically miss the key cue.
Which side moves first?
Black to move; the first move of the solution is h4f6.
What concepts does it train?
10 SAE-derived patterns including Detects kings in near-opposition or close proximity in…; Kings are in close proximity in an endgame, with one side…; King in an endgame position with no immediate threats….
Can I attempt it without an account?
Yes — Climbchess requires no signup or email. Click the trainer link to play the position interactively.