Detects a king on the back rank, with no pieces on the rank behind it.
SAE concept sae_1808 fires when detects a king on the back rank, with no pieces on the rank behind it.. It appears in 39 of 9,950 Climbchess puzzles (0.4%), spanning ELO 632–2343 (median 1049).
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This page documents Detects a king on the back rank, with no 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:
Detects a king on the back rank, with no pieces on the rank behind it.
This pattern fires in 39 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 632 to 2343, with a median rating of 1049. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_1808 |
|---|---|
| Puzzles where it fires | 39 |
| Min ELO | 632 |
| Median ELO | 1049 |
| Max ELO | 2343 |
| Coverage | 0.39% 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 00uEf — ELO 632, themes: endgame, mate, mateIn2, side to move: Black
- Puzzle OgxTs_M — ELO 650, themes: advancedPawn, bishopEndgame, crushing, side to move: White
- Puzzle z5QSy_M — ELO 730, themes: crushing, discoveredAttack, endgame, side to move: Black
- Puzzle zwocD_M — ELO 826, themes: advantage, endgame, fork, side to move: Black
- Puzzle yELhy_M — ELO 875, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle 027fm_M — ELO 1049, themes: crushing, endgame, fork, side to move: White
- Puzzle zv1cI — ELO 1202, themes: crushing, endgame, hangingPiece, side to move: Black
- Puzzle zhD42 — ELO 1414, themes: advantage, bishopEndgame, deflection, side to move: Black
- Puzzle 01LIu_M — ELO 1835, themes: crushing, endgame, master, side to move: White
- Puzzle zTimH_M — ELO 2059, themes: endgame, long, mate, 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_1808?
Detects a king on the back rank, with no pieces on the rank behind 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 39 tagged puzzles (0.4% of the set), spanning Lichess ELO 632 to 2343 with a median of 1049.
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.