Puzzle 01gpx_F — ELO 2071
This is a White-to-move puzzle rated 2071 ELO. The first move is b5b6, tagged with 10 interpretable concepts and Lichess themes: advancedPawn, crushing, defensiveMove.
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Position
White to move. ELO 2071. Themes: advancedPawn, crushing, defensiveMove, endgame, rookEndgame, veryLong.
FEN: 8/7p/8/1P6/4p2P/P1ppk3/7R/4K3 w - - 0 51
Show solution (10 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: b5b6 d3d2 e1d1 e3d3 h2h3 e4e3 h3e3 d3e3 d1c2 e3e2
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 An advanced passed pawn close to promotion in an endgame, with both sides…, which appears in only 62 of our 9,950 puzzles (0.62%). 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 2071 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?
2071 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 b5b6.
What concepts does it train?
10 SAE-derived patterns including Detects an empty square on the first rank that is attacked…; Passed pawn endgame with king opposition and advanced…; King actively centralised in a late endgame (pawn or minor….
Can I attempt it without an account?
Yes — Climbchess requires no signup or email. Click the trainer link to play the position interactively.