Detects an uncastled white king on e1 with the h1 rook still on its starting square and kingside castling rights intact.

By · · 3 min read · Updated May 8, 2026

SAE concept sae_25149 fires when detects an uncastled white king on e1 with the h1 rook still on its starting square and kingside castling rights intact.. It appears in 46 of 9,950 Climbchess puzzles (0.5%), spanning ELO 668–2401 (median 1600).

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This page documents Detects an uncastled white king on e1 with the…, 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:

Detects an uncastled white king on e1 with the h1 rook still on its starting square and kingside castling rights intact.

This pattern fires in 46 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 668 to 2401, with a median rating of 1600. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Concept IDsae_25149
Puzzles where it fires46
Min ELO668
Median ELO1600
Max ELO2401
Coverage0.46% 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.

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_25149?

Detects an uncastled white king on e1 with the h1 rook still on its starting square and kingside castling rights intact. 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 46 tagged puzzles (0.5% of the set), spanning Lichess ELO 668 to 2401 with a median of 1600.

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.