Pawn on the 4th, 5th, or 6th rank that is attacked by at least 2 enemy pieces and defended by 0 friendly pieces.
SAE concept sae_3400 fires when pawn on the 4th, 5th, or 6th rank that is attacked by at least 2 enemy pieces and defended by 0 friendly pieces.. It appears in 59 of 9,950 Climbchess puzzles (0.6%), spanning ELO 632–2483 (median 1754).
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This page documents Pawn on the 4th, 5th, or 6th rank that is…, 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 on the 4th, 5th, or 6th rank that is attacked by at least 2 enemy pieces and defended by 0 friendly pieces.
This pattern fires in 59 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 632 to 2483, with a median rating of 1754. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_3400 |
|---|---|
| Puzzles where it fires | 59 |
| Min ELO | 632 |
| Median ELO | 1754 |
| Max ELO | 2483 |
| Coverage | 0.59% 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 zujzx — ELO 632, themes: crushing, endgame, hangingPiece, side to move: Black
- Puzzle xR1pO_F — ELO 799, themes: anastasiaMate, endgame, master, side to move: White
- Puzzle zyTEc — ELO 888, themes: endgame, epauletteMate, mate, side to move: Black
- Puzzle zxCPw_F — ELO 1228, themes: advantage, discoveredAttack, kingsideAttack, side to move: White
- Puzzle zy6wx_M — ELO 1567, themes: advantage, endgame, pin, side to move: White
- Puzzle zhfCa_F — ELO 1754, themes: crushing, discoveredAttack, endgame, side to move: White
- Puzzle zxNXO_F — ELO 1810, themes: crushing, long, master, side to move: Black
- Puzzle zqWjJ_F — ELO 2020, themes: attraction, endgame, mate, side to move: White
- Puzzle zhqku_M — ELO 2116, themes: advantage, endgame, long, side to move: White
- Puzzle 7AmvP — ELO 2448, themes: deflection, hookMate, mate, 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_3400?
Pawn on the 4th, 5th, or 6th rank that is attacked by at least 2 enemy pieces and defended by 0 friendly pieces. 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 59 tagged puzzles (0.6% of the set), spanning Lichess ELO 632 to 2483 with a median of 1754.
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.