A trapped or immobile knight in a king-and-pawn or minor-piece endgame, where the opposing king manoeuvres to win the knight or exploit its restriction.
SAE concept sae_21891 fires when a trapped or immobile knight in a king-and-pawn or minor-piece endgame, where the opposing king manoeuvres to win the knight or exploit its restriction.. It appears in 11 of 9,950 Climbchess puzzles (0.1%), spanning ELO 829–2444 (median 843).
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This page documents A trapped or immobile knight in a king-and-pawn…, 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 trapped or immobile knight in a king-and-pawn or minor-piece endgame, where the opposing king manoeuvres to win the knight or exploit its restriction.
This pattern fires in 11 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 829 to 2444, with a median rating of 843. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_21891 |
|---|---|
| Puzzles where it fires | 11 |
| Min ELO | 829 |
| Median ELO | 843 |
| Max ELO | 2444 |
| Coverage | 0.11% 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 QEesa — ELO 829, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle QEesa_F — ELO 829, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle QEesa_M — ELO 829, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zaLk1 — ELO 843, themes: crushing, endgame, master, side to move: White
- Puzzle zaLk1_F — ELO 843, themes: crushing, endgame, master, side to move: Black
- Puzzle zaLk1_M — ELO 843, themes: crushing, endgame, master, side to move: White
- Puzzle zq1uH_M — ELO 1015, themes: clearance, kingsideAttack, mate, side to move: Black
- Puzzle zv9yf — ELO 1996, themes: advantage, defensiveMove, endgame, side to move: Black
- Puzzle zv9yf_F — ELO 1996, themes: advantage, defensiveMove, endgame, side to move: White
- Puzzle zv9yf_M — ELO 1996, themes: advantage, defensiveMove, endgame, 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_21891?
A trapped or immobile knight in a king-and-pawn or minor-piece endgame, where the opposing king manoeuvres to win the knight or exploit its restriction. 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 11 tagged puzzles (0.1% of the set), spanning Lichess ELO 829 to 2444 with a median of 843.
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.