King endgame with active king opposition or key square control (pawn or bishop endgame).
SAE concept sae_20903 fires when king endgame with active king opposition or key square control (pawn or bishop endgame).. It appears in 17 of 9,950 Climbchess puzzles (0.2%), spanning ELO 1368–2698 (median 1918).
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This page documents King endgame with active king opposition or key…, 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:
King endgame with active king opposition or key square control (pawn or bishop endgame).
This pattern fires in 17 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 1368 to 2698, with a median rating of 1918. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_20903 |
|---|---|
| Puzzles where it fires | 17 |
| Min ELO | 1368 |
| Median ELO | 1918 |
| Max ELO | 2698 |
| Coverage | 0.17% 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 zpo0D_M — ELO 1368, themes: crushing, endgame, pawnEndgame, side to move: White
- Puzzle 01hHF — ELO 1611, themes: bishopEndgame, crushing, endgame, side to move: Black
- Puzzle 01hHF_M — ELO 1611, themes: bishopEndgame, crushing, endgame, side to move: Black
- Puzzle zsFmZ — ELO 1655, themes: bishopEndgame, crushing, endgame, side to move: White
- Puzzle zsFmZ_F — ELO 1655, themes: bishopEndgame, crushing, endgame, side to move: Black
- Puzzle zys4h — ELO 1918, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zys4h_M — ELO 1918, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zgw3O — ELO 2049, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zgw3O_M — ELO 2049, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle 020IV_F — ELO 2698, themes: advantage, endgame, pawnEndgame, 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_20903?
King endgame with active king opposition or key square control (pawn or bishop endgame). 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 17 tagged puzzles (0.2% of the set), spanning Lichess ELO 1368 to 2698 with a median of 1918.
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.