Detects an empty square attacked by exactly one black piece, with no white attackers, and the white king is nearby.

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

SAE concept sae_5923 fires when detects an empty square attacked by exactly one black piece, with no white attackers, and the white king is nearby.. It appears in 9 of 9,950 Climbchess puzzles (0.1%), spanning ELO 1924–2598 (median 2206).

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This page documents Detects an empty square attacked by exactly one…, 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 empty square attacked by exactly one black piece, with no white attackers, and the white king is nearby.

This pattern fires in 9 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 1924 to 2598, with a median rating of 2206. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Concept IDsae_5923
Puzzles where it fires9
Min ELO1924
Median ELO2206
Max ELO2598
Coverage0.09% 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 9 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_5923?

Detects an empty square attacked by exactly one black piece, with no white attackers, and the white king is nearby. 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 9 tagged puzzles (0.1% of the set), spanning Lichess ELO 1924 to 2598 with a median of 2206.

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.