Two white bishops coordinating to deliver or threaten double-bishop mate, with the light-square bishop active and uncontested.

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

SAE concept sae_6870 fires when two white bishops coordinating to deliver or threaten double-bishop mate, with the light-square bishop active and uncontested.. It appears in 3 of 9,950 Climbchess puzzles (0.0%), spanning ELO 907–907 (median 907).

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This page documents Two white bishops coordinating to deliver 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:

Two white bishops coordinating to deliver or threaten double-bishop mate, with the light-square bishop active and uncontested.

This pattern fires in 3 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 907 to 907, with a median rating of 907. 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 active near the opponent's back rank enabling a mating attack… — similarity 0.188
• Black bishop infiltrated to the 2nd rank (a2 or h2 area) as part of a… — similarity 0.176
• White king retains castling rights and is surrounded by friendly pieces, with… — similarity 0.005
• Detects white rooks on their starting squares (d1, e1, f1) in middlegame… — similarity 0.004
• White king on the back rank (e1–g1 area) in a tactical position with active… — similarity 0.003

Example puzzles

Below are 3 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.

• Puzzle yjpKK — ELO 907, themes: doubleBishopMate, mate, mateIn1, side to move: White
• Puzzle yjpKK_F — ELO 907, themes: doubleBishopMate, mate, mateIn1, side to move: Black
• Puzzle yjpKK_M — ELO 907, themes: doubleBishopMate, mate, mateIn1, 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).