Detects an active black bishop in an endgame, typically on a central or semi-central diagonal, with minimal opposition pressure.

By Climbchess Research · 2026-05-08 · 3 min read · Updated May 8, 2026

SAE concept sae_2164 fires when detects an active black bishop in an endgame, typically on a central or semi-central diagonal, with minimal opposition pressure.. It appears in 118 of 9,950 Climbchess puzzles (1.2%), spanning ELO 687–2600 (median 1184).

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This page documents Detects an active black bishop in an endgame…, 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 active black bishop in an endgame, typically on a central or semi-central diagonal, with minimal opposition pressure.

This pattern fires in 118 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 687 to 2600, with a median rating of 1184. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Related concepts

The five concepts most often co-firing alongside this one (Jaccard similarity over the puzzle co-occurrence graph) are:

• Black bishop actively placed in an endgame, often contesting the same diagonal… — similarity 0.089
• Active bishop (either colour) in an endgame with back-rank mating threats or… — similarity 0.069
• A black piece on a contested square where black retains at least partial… — similarity 0.068
• King on rank 2 or 7 in a simplified endgame, often with passed pawns or mating… — similarity 0.061
• A rook poised to deliver or support a back-rank mate, often on an open file… — similarity 0.052

Example puzzles

Below are 10 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.

• Puzzle zv890_M — ELO 687, themes: backRankMate, endgame, mate, side to move: White
• Puzzle zbFfw_F — ELO 791, themes: deflection, discoveredAttack, endgame, side to move: White
• Puzzle 01HU7_F — ELO 844, themes: endgame, mate, mateIn1, side to move: White
• Puzzle ug1j3_M — ELO 885, themes: crushing, endgame, master, side to move: Black
• Puzzle 01SLc_M — ELO 960, themes: crushing, deflection, endgame, side to move: Black
• Puzzle xwNOy_M — ELO 1184, themes: bishopEndgame, doubleBishopMate, endgame, side to move: Black
• Puzzle zpr2o — ELO 1653, themes: advancedPawn, bishopEndgame, crushing, side to move: White
• Puzzle zhfCa — ELO 1754, themes: crushing, discoveredAttack, endgame, side to move: Black
• Puzzle ztSDk_M — ELO 2041, themes: crushing, endgame, long, side to move: White
• Puzzle 01qVU — ELO 2311, themes: advancedPawn, crushing, endgame, side to move: White

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).