Empty squares on the back rank in an active king endgame, relevant to king mobility and zugzwang calculation.
SAE concept sae_13107 fires when empty squares on the back rank in an active king endgame, relevant to king mobility and zugzwang calculation.. It appears in 163 of 9,950 Climbchess puzzles (1.6%), spanning ELO 614–2675 (median 1681).
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This page documents Empty squares on the back rank in an active king…, 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:
Empty squares on the back rank in an active king endgame, relevant to king mobility and zugzwang calculation.
This pattern fires in 163 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 614 to 2675, with a median rating of 1681. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_13107 |
|---|---|
| Puzzles where it fires | 163 |
| Min ELO | 614 |
| Median ELO | 1681 |
| Max ELO | 2675 |
| Coverage | 1.64% 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 zzNuy — ELO 614, themes: advancedPawn, crushing, endgame, side to move: White
- Puzzle zmqww — ELO 947, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zlrEp — ELO 1107, themes: crushing, endgame, master, side to move: White
- Puzzle zypSs — ELO 1427, themes: crushing, endgame, exposedKing, side to move: White
- Puzzle 01IjU_M — ELO 1616, themes: crushing, endgame, long, side to move: Black
- Puzzle 027Iu — ELO 1681, themes: crushing, defensiveMove, endgame, side to move: Black
- Puzzle zvlwh_F — ELO 1777, themes: advancedPawn, crushing, defensiveMove, side to move: White
- Puzzle zzNOQ — ELO 2025, themes: advantage, endgame, hangingPiece, side to move: White
- Puzzle 00ZSu_M — ELO 2143, themes: advantage, endgame, rookEndgame, side to move: Black
- Puzzle yqA7A_M — ELO 2417, themes: crushing, endgame, hangingPiece, 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_13107?
Empty squares on the back rank in an active king endgame, relevant to king mobility and zugzwang calculation. 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 163 tagged puzzles (1.6% of the set), spanning Lichess ELO 614 to 2675 with a median of 1681.
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.