Black king on e8 with at least two black pieces defending squares adjacent to it.
SAE concept sae_2425 fires when black king on e8 with at least two black pieces defending squares adjacent to it.. It appears in 216 of 9,950 Climbchess puzzles (2.2%), spanning ELO 650–2694 (median 1572).
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This page documents Black king on e8 with at least two black pieces…, 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:
Black king on e8 with at least two black pieces defending squares adjacent to it.
This pattern fires in 216 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 650 to 2694, with a median rating of 1572. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_2425 |
|---|---|
| Puzzles where it fires | 216 |
| Min ELO | 650 |
| Median ELO | 1572 |
| Max ELO | 2694 |
| Coverage | 2.17% 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 zqC5Y — ELO 650, themes: hangingPiece, mate, mateIn1, side to move: Black
- Puzzle zsFgQ_F — ELO 913, themes: advantage, hangingPiece, middlegame, side to move: White
- Puzzle yu9Mj_F — ELO 1173, themes: crushing, interference, opening, side to move: Black
- Puzzle 0279c — ELO 1303, themes: attackingF2F7, master, mate, side to move: White
- Puzzle zxCNN — ELO 1480, themes: advantage, middlegame, pin, side to move: White
- Puzzle zzzKH_F — ELO 1572, themes: crushing, fork, master, side to move: Black
- Puzzle zuUb5 — ELO 1689, themes: advantage, attraction, fork, side to move: White
- Puzzle zzqAy — ELO 1858, themes: advancedPawn, advantage, opening, side to move: White
- Puzzle 01xUb_F — ELO 2109, themes: advantage, opening, pin, side to move: White
- Puzzle xf87P — ELO 2412, themes: advantage, master, middlegame, 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_2425?
Black king on e8 with at least two black pieces defending squares adjacent to it. 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 216 tagged puzzles (2.2% of the set), spanning Lichess ELO 650 to 2694 with a median of 1572.
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.