A pawn on the 4th or 5th rank is attacked by an enemy pawn and defended by a friendly pawn, with the attacking pawn being on an adjacent file.
SAE concept sae_31412 fires when a pawn on the 4th or 5th rank is attacked by an enemy pawn and defended by a friendly pawn, with the attacking pawn being on an adjacent file.. It appears in 27 of 9,950 Climbchess puzzles (0.3%), spanning ELO 891–2211 (median 1405).
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This page documents A pawn on the 4th or 5th rank is attacked by an…, 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 pawn on the 4th or 5th rank is attacked by an enemy pawn and defended by a friendly pawn, with the attacking pawn being on an adjacent file.
This pattern fires in 27 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 891 to 2211, with a median rating of 1405. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_31412 |
|---|---|
| Puzzles where it fires | 27 |
| Min ELO | 891 |
| Median ELO | 1405 |
| Max ELO | 2211 |
| Coverage | 0.27% 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 zt9Jj — ELO 891, themes: advancedPawn, crushing, endgame, side to move: Black
- Puzzle zvpPB — ELO 934, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle zu4Fq — ELO 1143, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zdyQ6 — ELO 1165, themes: crushing, endgame, pawnEndgame, side to move: White
- Puzzle zdyQ6_M — ELO 1165, themes: crushing, endgame, pawnEndgame, side to move: White
- Puzzle zsYWx — ELO 1405, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle 00ME0 — ELO 1626, themes: bishopEndgame, crushing, endgame, side to move: Black
- Puzzle zzXZD_M — ELO 1707, themes: advancedPawn, crushing, deflection, side to move: Black
- Puzzle zTHBT_M — ELO 1900, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle zRiv6 — ELO 2188, themes: crushing, endgame, 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_31412?
A pawn on the 4th or 5th rank is attacked by an enemy pawn and defended by a friendly pawn, with the attacking pawn being on an adjacent file. 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 27 tagged puzzles (0.3% of the set), spanning Lichess ELO 891 to 2211 with a median of 1405.
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.