Pawn endgame with a locked or near-locked pawn structure where zugzwang or a passed pawn determines the outcome.
SAE concept sae_12249 fires when pawn endgame with a locked or near-locked pawn structure where zugzwang or a passed pawn determines the outcome.. It appears in 49 of 9,950 Climbchess puzzles (0.5%), spanning ELO 605–2580 (median 1573).
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This page documents Pawn endgame with a locked or near-locked 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:
Pawn endgame with a locked or near-locked pawn structure where zugzwang or a passed pawn determines the outcome.
This pattern fires in 49 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 605 to 2580, with a median rating of 1573. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_12249 |
|---|---|
| Puzzles where it fires | 49 |
| Min ELO | 605 |
| Median ELO | 1573 |
| Max ELO | 2580 |
| Coverage | 0.49% 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 yS8nE_M — ELO 605, themes: crushing, endgame, long, side to move: Black
- Puzzle ztZsb — ELO 1031, themes: crushing, defensiveMove, endgame, side to move: White
- Puzzle zw25T_M — ELO 1090, themes: advancedPawn, endgame, exposedKing, side to move: White
- Puzzle xNepc_M — ELO 1182, themes: crushing, endgame, pawnEndgame, side to move: Black
- Puzzle zYmF8_F — ELO 1341, themes: crushing, endgame, pawnEndgame, side to move: Black
- Puzzle 01rpc_F — ELO 1573, themes: crushing, endgame, long, side to move: White
- Puzzle znd3D — ELO 1794, themes: crushing, endgame, long, side to move: Black
- Puzzle zqazk_M — ELO 1907, themes: crushing, endgame, long, side to move: Black
- Puzzle zeSQD_M — ELO 2236, themes: crushing, endgame, long, side to move: White
- Puzzle zYxVq — ELO 2574, themes: crushing, 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_12249?
Pawn endgame with a locked or near-locked pawn structure where zugzwang or a passed pawn determines the outcome. 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 49 tagged puzzles (0.5% of the set), spanning Lichess ELO 605 to 2580 with a median of 1573.
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.