Puzzle zfOmW — ELO 2642
This is a Black-to-move puzzle rated 2642 ELO. The first move is c3f3, tagged with 10 interpretable concepts and Lichess themes: attraction, crushing, exposedKing.
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Position
Black to move. ELO 2642. Themes: attraction, crushing, exposedKing, middlegame, sacrifice, skewer, veryLong.
FEN: 5k1r/pp2q3/3RbpQ1/4p3/8/2r2N2/P1P2PRP/2K5 b - - 0 23
Show solution (10 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: c3f3 d6e6 e7f7 g6g4 f3f4 e6e8 f8e8 g4c8 e8e7 c8h8
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 White has pieces defending the king's starting zone (back rank) while black…, which appears in only 637 of our 9,950 puzzles (6.40%). 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 2642 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?
2642 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 c3f3.
What concepts does it train?
10 SAE-derived patterns including White Queen on the 1st or 2nd rank, unthreatened by black…; A black queen on a central or open file, not attacked by…; This feature detects a white queen on a square where it is….
Can I attempt it without an account?
Yes — Climbchess requires no signup or email. Click the trainer link to play the position interactively.