Detects a queen on the home-side back ranks (1st–2nd for white, 7th–8th for black) that is well-defended and not under attack, across both colour orientations.

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

SAE concept sae_18888 fires when detects a queen on the home-side back ranks (1st–2nd for white, 7th–8th for black) that is well-defended and not under attack, across both colour orientations.. It appears in 1,010 of 9,950 Climbchess puzzles (10.2%), spanning ELO 610–2694 (median 1744).

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This page documents Detects a queen on the home-side back ranks…, 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 a queen on the home-side back ranks (1st–2nd for white, 7th–8th for black) that is well-defended and not under attack, across both colour orientations.

This pattern fires in 1,010 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 610 to 2694, with a median rating of 1744. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Concept IDsae_18888
Puzzles where it fires1,010
Min ELO610
Median ELO1744
Max ELO2694
Coverage10.15% 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_18888?

Detects a queen on the home-side back ranks (1st–2nd for white, 7th–8th for black) that is well-defended and not under attack, across both colour orientations. 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 1,010 tagged puzzles (10.2% of the set), spanning Lichess ELO 610 to 2694 with a median of 1744.

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.