A white pawn on the 4th rank is under pressure with the advance square as the key target, though attack and defence conditions are not always present.
SAE concept sae_38406 fires when a white pawn on the 4th rank is under pressure with the advance square as the key target, though attack and defence conditions are not always present.. It appears in 71 of 9,950 Climbchess puzzles (0.7%), spanning ELO 802–2586 (median 1626).
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This page documents A white pawn on the 4th rank is under pressure…, 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:
A white pawn on the 4th rank is under pressure with the advance square as the key target, though attack and defence conditions are not always present.
This pattern fires in 71 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 802 to 2586, with a median rating of 1626. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_38406 |
|---|---|
| Puzzles where it fires | 71 |
| Min ELO | 802 |
| Median ELO | 1626 |
| Max ELO | 2586 |
| Coverage | 0.71% of puzzle set |
Related concepts
The five concepts most often co-firing alongside this one (Jaccard similarity over the puzzle co-occurrence graph) are:
Example puzzles
Below are 10 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.
- Puzzle zZGI0 — ELO 802, themes: crushing, endgame, pawnEndgame, side to move: Black
- Puzzle zN1WI_F — ELO 1118, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle zu4Fq_M — ELO 1143, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zpqLt_M — ELO 1291, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle xHSCs — ELO 1599, themes: endgame, hookMate, master, side to move: White
- Puzzle 00ME0_F — ELO 1626, themes: bishopEndgame, crushing, endgame, side to move: White
- Puzzle zpW9Z_M — ELO 1851, themes: crushing, endgame, long, side to move: White
- Puzzle zzzOI_M — ELO 1903, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle zqWjJ_F — ELO 2020, themes: attraction, endgame, mate, side to move: White
- Puzzle zzAqy_F — ELO 2286, themes: endgame, exposedKing, long, 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).
Frequently asked
What is SAE concept sae_38406?
A white pawn on the 4th rank is under pressure with the advance square as the key target, though attack and defence conditions are not always present. It is one of 4,505 interpretable features extracted from Leela Chess Zero's residual stream via sparse autoencoders, then labelled by reading the top-activating positions.
Where does this pattern appear?
In 71 tagged puzzles (0.7% of the set), spanning Lichess ELO 802 to 2586 with a median of 1626.
How do I train it?
Open the Climbchess trainer and filter for puzzles tagged with this concept. The trainer adapts difficulty using your live recognition profile and tracks how often you spot the cue versus miss it.
Is it free?
Yes. Climbchess is free forever, with no account, email, or signup required. You can delete your data at any time.