Detects a knight fork threat on the king and another piece (rook, queen, or pawn) where the knight is not attacked.

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

SAE concept sae_18970 fires when detects a knight fork threat on the king and another piece (rook, queen, or pawn) where the knight is not attacked.. It appears in 1 of 9,950 Climbchess puzzles (0.0%), spanning ELO 2072–2072 (median 2072).

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This page documents Detects a knight fork threat on the king and…, 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 fork threat on the king and another piece (rook, queen, or pawn) where the knight is not attacked.

This pattern fires in 1 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 2072 to 2072, with a median rating of 2072. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Concept IDsae_18970
Puzzles where it fires1
Min ELO2072
Median ELO2072
Max ELO2072
Coverage0.01% 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 1 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_18970?

Detects a knight fork threat on the king and another piece (rook, queen, or pawn) where the knight is not attacked. 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 tagged puzzles (0.0% of the set), spanning Lichess ELO 2072 to 2072 with a median of 2072.

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.