The feature detects a black pawn on a7, with no attackers or defenders, and a white pawn on a2 or a3, and a white bishop on the a1-h8 diagonal.
SAE concept sae_18876 fires when the feature detects a black pawn on a7, with no attackers or defenders, and a white pawn on a2 or a3, and a white bishop on the a1-h8 diagonal.. It appears in 2 of 9,950 Climbchess puzzles (0.0%), spanning ELO 1641–2428 (median 2428).
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This page documents The feature detects a black pawn on a7, with no…, 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:
The feature detects a black pawn on a7, with no attackers or defenders, and a white pawn on a2 or a3, and a white bishop on the a1-h8 diagonal.
This pattern fires in 2 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 1641 to 2428, with a median rating of 2428. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_18876 |
|---|---|
| Puzzles where it fires | 2 |
| Min ELO | 1641 |
| Median ELO | 2428 |
| Max ELO | 2428 |
| Coverage | 0.02% 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 2 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.
- Puzzle zsKzr_M — ELO 1641, themes: advantage, defensiveMove, endgame, side to move: Black
- Puzzle zKJvp_M — ELO 2428, themes: crushing, endgame, long, side to move: Black
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_18876?
The feature detects a black pawn on a7, with no attackers or defenders, and a white pawn on a2 or a3, and a white bishop on the a1-h8 diagonal. 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 2 tagged puzzles (0.0% of the set), spanning Lichess ELO 1641 to 2428 with a median of 2428.
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.