Puzzle zyv2u — ELO 1969
This is a White-to-move puzzle rated 1969 ELO. The first move is c4c5, tagged with 10 interpretable concepts and Lichess themes: advancedPawn, crushing, endgame.
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Position
White to move. ELO 1969. Themes: advancedPawn, crushing, endgame, pawnEndgame, promotion, quietMove, veryLong.
FEN: 8/p1p5/8/8/P1P3k1/1P3p2/5K2/8 w - - 0 54
Show solution (10 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: c4c5 a7a5 b3b4 a5b4 a4a5 b4b3 a5a6 b3b2 a6a7 b2b1q
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 Squares vulnerable to enemy pawn attack with insufficient local defence, which appears in only 5 of our 9,950 puzzles (0.05%). 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 1969 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?
1969 Lichess ELO. Solvers below that rating typically miss the key cue.
Which side moves first?
White to move; the first move of the solution is c4c5.
What concepts does it train?
10 SAE-derived patterns including Active king in a king-and-pawn endgame, often on the…; King actively centralised in a late endgame (pawn or minor…; 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.