A white pawn advanced to the 5th or 6th rank that is attacked by two or more black pieces and is a focal point of the position's tension.
SAE concept sae_1909 fires when a white pawn advanced to the 5th or 6th rank that is attacked by two or more black pieces and is a focal point of the position's tension.. It appears in 28 of 9,950 Climbchess puzzles (0.3%), spanning ELO 917–2595 (median 1892).
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This page documents A white pawn advanced to the 5th or 6th rank…, 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 advanced to the 5th or 6th rank that is attacked by two or more black pieces and is a focal point of the position's tension.
This pattern fires in 28 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 917 to 2595, with a median rating of 1892. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_1909 |
|---|---|
| Puzzles where it fires | 28 |
| Min ELO | 917 |
| Median ELO | 1892 |
| Max ELO | 2595 |
| Coverage | 0.28% 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 z7zdj — ELO 917, themes: arabianMate, mate, mateIn2, side to move: Black
- Puzzle z7zdj_M — ELO 917, themes: arabianMate, mate, mateIn2, side to move: Black
- Puzzle zXOsz_F — ELO 1055, themes: attraction, kingsideAttack, mate, side to move: Black
- Puzzle zzs6a_M — ELO 1390, themes: advantage, endgame, fork, side to move: White
- Puzzle zzGAy_F — ELO 1436, themes: crushing, endgame, long, side to move: White
- Puzzle zzlNM_M — ELO 1892, themes: endgame, long, mate, side to move: Black
- Puzzle zgto8_F — ELO 2037, themes: clearance, crushing, endgame, side to move: White
- Puzzle zxzq2 — ELO 2275, themes: crushing, deflection, kingsideAttack, side to move: Black
- Puzzle ztTGN — ELO 2568, themes: advantage, attraction, long, side to move: Black
- Puzzle yQjaB_M — ELO 2574, themes: advancedPawn, crushing, 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_1909?
A white pawn advanced to the 5th or 6th rank that is attacked by two or more black pieces and is a focal point of the position's tension. 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 28 tagged puzzles (0.3% of the set), spanning Lichess ELO 917 to 2595 with a median of 1892.
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.