White rook on its starting square (a1, c1, g1) with no white pieces on the 2nd rank and no black pieces on the 1st or 2nd rank, indicating an open or semi-open file for the rook.
SAE concept sae_3121 fires when white rook on its starting square (a1, c1, g1) with no white pieces on the 2nd rank and no black pieces on the 1st or 2nd rank, indicating an open or semi-open file for the rook.. It appears in 104 of 9,950 Climbchess puzzles (1.0%), spanning ELO 712–2586 (median 1125).
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This page documents White rook on its starting square (a1, c1, g1)…, 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:
White rook on its starting square (a1, c1, g1) with no white pieces on the 2nd rank and no black pieces on the 1st or 2nd rank, indicating an open or semi-open file for the rook.
This pattern fires in 104 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 712 to 2586, with a median rating of 1125. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_3121 |
|---|---|
| Puzzles where it fires | 104 |
| Min ELO | 712 |
| Median ELO | 1125 |
| Max ELO | 2586 |
| Coverage | 1.05% 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 zlNFE — ELO 712, themes: advancedPawn, backRankMate, endgame, side to move: Black
- Puzzle zXfDF_F — ELO 769, themes: arabianMate, endgame, mate, side to move: Black
- Puzzle sgNLg_M — ELO 820, themes: endgame, hookMate, mate, side to move: Black
- Puzzle zrqWF — ELO 930, themes: arabianMate, endgame, mate, side to move: White
- Puzzle zGRe5_F — ELO 1007, themes: crushing, endgame, short, side to move: White
- Puzzle ziKY4 — ELO 1125, themes: endgame, exposedKing, hookMate, side to move: Black
- Puzzle zwCbp_M — ELO 1273, themes: crushing, deflection, endgame, side to move: Black
- Puzzle zziy3_F — ELO 1481, themes: endgame, mate, mateIn2, side to move: White
- Puzzle zKtuI_F — ELO 2102, themes: blindSwineMate, endgame, long, side to move: White
- Puzzle zxQ8A_M — ELO 2317, themes: advantage, endgame, quietMove, 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_3121?
White rook on its starting square (a1, c1, g1) with no white pieces on the 2nd rank and no black pieces on the 1st or 2nd rank, indicating an open or semi-open file for the rook. 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 104 tagged puzzles (1.0% of the set), spanning Lichess ELO 712 to 2586 with a median of 1125.
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.