Detects king and pawn structures in pawn endgames where the king supports a passed or advanced pawn from close proximity.

By Climbchess Research · 2026-05-08 · 3 min read · Updated May 8, 2026

SAE concept sae_8122 fires when detects king and pawn structures in pawn endgames where the king supports a passed or advanced pawn from close proximity.. It appears in 5 of 9,950 Climbchess puzzles (0.1%), spanning ELO 1795–2333 (median 2333).

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This page documents Detects king and pawn structures in pawn…, one of 4,505 interpretable chess concepts extracted from Leela Chess Zero via sparse autoencoders. The full feature description from our SAE labelling pipeline reads:

Detects king and pawn structures in pawn endgames where the king supports a passed or advanced pawn from close proximity.

This pattern fires in 5 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 1795 to 2333, with a median rating of 2333. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Related concepts

The five concepts most often co-firing alongside this one (Jaccard similarity over the puzzle co-occurrence graph) are:

• White pawn on the 2nd, 3rd, or 4th rank with no black attackers, in a pawn… — similarity 0.111
• A square in the central pawn structure attacked by Black with no White… — similarity 0.041
• Rook endgame with a king-centralisation or fork motif, often with mutual pawn… — similarity 0.026
• Detects pawn endgame positions with multiple advanced passed or candidate… — similarity 0.020
• King active on central or near-central ranks (3rd–6th) in a king-and-pawn… — similarity 0.018

Example puzzles

Below are 5 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.

• Puzzle zTwNF — ELO 1795, themes: crushing, endgame, long, side to move: Black
• Puzzle zTwNF_F — ELO 1795, themes: crushing, endgame, long, side to move: White
• Puzzle 01zXC — ELO 2333, themes: crushing, defensiveMove, endgame, side to move: White
• Puzzle 01zXC_F — ELO 2333, themes: crushing, defensiveMove, endgame, side to move: Black
• Puzzle 01zXC_M — ELO 2333, themes: crushing, defensiveMove, endgame, side to move: White

How to use this page

If you want to train this pattern, open the Climbchess trainer and filter for puzzles tagged with this concept. The trainer surfaces them at the right difficulty for your current rating, and tracks how often you spot the cue versus miss it. You can also browse the related concepts above to see neighbouring ideas in feature space.

Climbchess concepts are not heuristics written by a human author. Each one corresponds to a single direction in the residual stream of Leela Chess Zero that activates on a specific board feature, then was labelled by reading the top-activating positions. This makes the catalogue exhaustive (every Leela-detectable pattern is in here somewhere) and falsifiable (you can replay our extraction).