Black king trapped or restricted on the back rank, vulnerable to a discovered attack, pin, or back-rank mate threat from white.
SAE concept sae_29102 fires when black king trapped or restricted on the back rank, vulnerable to a discovered attack, pin, or back-rank mate threat from white.. It appears in 557 of 9,950 Climbchess puzzles (5.6%), spanning ELO 610–2694 (median 1390).
Free forever · no email · no signup · delete data anytime.
This page documents Black king trapped or restricted on the back…, 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:
Black king trapped or restricted on the back rank, vulnerable to a discovered attack, pin, or back-rank mate threat from white.
This pattern fires in 557 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 610 to 2694, with a median rating of 1390. That distribution tells you whether this is a beginner cue or a master-level subtlety.
Pattern statistics
| Concept ID | sae_29102 |
|---|---|
| Puzzles where it fires | 557 |
| Min ELO | 610 |
| Median ELO | 1390 |
| Max ELO | 2694 |
| Coverage | 5.60% 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 ydABK — ELO 610, themes: crushing, endgame, hangingPiece, side to move: White
- Puzzle zzPHE_F — ELO 812, themes: endgame, mate, mateIn2, side to move: White
- Puzzle zuXgA — ELO 923, themes: backRankMate, endgame, mate, side to move: White
- Puzzle 01rQs_M — ELO 1015, themes: long, mate, mateIn3, side to move: Black
- Puzzle zow07_F — ELO 1192, themes: advantage, middlegame, pin, side to move: Black
- Puzzle zzs6a_F — ELO 1390, themes: advantage, endgame, fork, side to move: Black
- Puzzle vHO3B — ELO 1659, themes: advantage, hangingPiece, long, side to move: White
- Puzzle zi4Ne_M — ELO 1881, themes: crushing, endgame, long, side to move: Black
- Puzzle 01vLC — ELO 2127, themes: crushing, endgame, long, side to move: Black
- Puzzle uuH2Y — ELO 2444, themes: advantage, 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_29102?
Black king trapped or restricted on the back rank, vulnerable to a discovered attack, pin, or back-rank mate threat from white. 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 557 tagged puzzles (5.6% of the set), spanning Lichess ELO 610 to 2694 with a median of 1390.
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.