Puzzle ziWOb_M — ELO 2553
This is a White-to-move puzzle rated 2553 ELO. The first move is b5b6, tagged with 10 interpretable concepts and Lichess themes: advancedPawn, advantage, deflection.
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Position
White to move. ELO 2553. Themes: advancedPawn, advantage, deflection, endgame, long, master, masterVsMaster, promotion, rookEndgame.
FEN: 2r5/8/7p/1P6/P6P/8/K4pk1/1R6 w - - 1 47
Show solution (6 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: b5b6 c8b8 a2a3 b8b6 b1b6 f2f1q
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 Moving piece lands on an empty square adjacent or near a friendly pawn, across…, which appears in only 24 of our 9,950 puzzles (0.24%). 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 2553 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?
2553 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 A white passed pawn on the 5th to 7th rank with promotion…; Pawn on the 7th rank (any file) that is advanced or…; Advanced passed pawn threatening promotion in an endgame….
Can I attempt it without an account?
Yes — Climbchess requires no signup or email. Click the trainer link to play the position interactively.