Endgame with active white rook or bishop co-ordinating with a passed pawn, king not on back rank.

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

SAE concept sae_22492 fires when endgame with active white rook or bishop co-ordinating with a passed pawn, king not on back rank.. It appears in 12 of 9,950 Climbchess puzzles (0.1%), spanning ELO 979–2675 (median 2396).

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This page documents Endgame with active white rook or bishop…, 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:

Endgame with active white rook or bishop co-ordinating with a passed pawn, king not on back rank.

This pattern fires in 12 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 979 to 2675, with a median rating of 2396. 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:

• A critical passed pawn or promotion threat in a complex endgame, often with… — similarity 0.158
• Detects an empty square on the first rank that is attacked by a pawn and… — similarity 0.050
• The feature detects an empty square on the first rank that is not attacked by… — similarity 0.047
• Empty squares on the back rank in an active king endgame, relevant to king… — similarity 0.042
• Passed pawn endgame with king opposition and advanced pawns racing to promote. — similarity 0.034

Example puzzles

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

• Puzzle zwnYN — ELO 979, themes: crushing, endgame, hangingPiece, side to move: White
• Puzzle zwnYN_F — ELO 979, themes: crushing, endgame, hangingPiece, side to move: Black
• Puzzle zwnYN_M — ELO 979, themes: crushing, endgame, hangingPiece, side to move: White
• Puzzle 01B8l — ELO 1370, themes: advantage, endgame, short, side to move: Black
• Puzzle 01B8l_F — ELO 1370, themes: advantage, endgame, short, side to move: White
• Puzzle zTNsL — ELO 2396, themes: advancedPawn, clearance, crushing, side to move: Black
• Puzzle zTNsL_F — ELO 2396, themes: advancedPawn, clearance, crushing, side to move: White
• Puzzle zTNsL_M — ELO 2396, themes: advancedPawn, clearance, crushing, side to move: Black
• Puzzle zFcdB — ELO 2675, themes: bishopEndgame, crushing, defensiveMove, side to move: White
• Puzzle zFcdB_F — ELO 2675, themes: bishopEndgame, crushing, defensiveMove, side to move: Black

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).