Detects a knight posted on a central or near-central square (c3–f5 region) that is under attack and defended, creating a tactical tension point in the position.

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

SAE concept sae_355 fires when detects a knight posted on a central or near-central square (c3–f5 region) that is under attack and defended, creating a tactical tension point in the position.. It appears in 991 of 9,950 Climbchess puzzles (10.0%), spanning ELO 670–2691 (median 1670).

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This page documents Detects a knight posted on a central or…, 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 knight posted on a central or near-central square (c3–f5 region) that is under attack and defended, creating a tactical tension point in the position.

This pattern fires in 991 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 670 to 2691, with a median rating of 1670. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Concept IDsae_355
Puzzles where it fires991
Min ELO670
Median ELO1670
Max ELO2691
Coverage9.96% 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_355?

Detects a knight posted on a central or near-central square (c3–f5 region) that is under attack and defended, creating a tactical tension point in the position. 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 991 tagged puzzles (10.0% of the set), spanning Lichess ELO 670 to 2691 with a median of 1670.

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.