Rook actively placed in a mating or forcing configuration, often participating in deflection, Pillsbury-style mates, or discovered attacks.

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

SAE concept sae_2255 fires when rook actively placed in a mating or forcing configuration, often participating in deflection, Pillsbury-style mates, or discovered attacks.. It appears in 104 of 9,950 Climbchess puzzles (1.0%), spanning ELO 724–2586 (median 1178).

Free forever · no email · no signup · delete data anytime.

This page documents Rook actively placed in a mating or forcing…, 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:

Rook actively placed in a mating or forcing configuration, often participating in deflection, Pillsbury-style mates, or discovered attacks.

This pattern fires in 104 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 724 to 2586, with a median rating of 1178. 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:

• Rook operating on an open file or rank as the key piece in a mating attack or… — similarity 0.088
• White rook actively placed on an open file or rank, often near the opponent's… — similarity 0.083
• King on rank 2 or 7 in a simplified endgame, often with passed pawns or mating… — similarity 0.063
• Rook endgame with active rook placement, often involving deflection… — similarity 0.059
• Active rook delivering or threatening a decisive mating attack in the endgame… — similarity 0.058

Example puzzles

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

• Puzzle st8SM — ELO 724, themes: crushing, endgame, interference, side to move: Black
• Puzzle zx0yA_F — ELO 808, themes: crushing, discoveredAttack, endgame, side to move: Black
• Puzzle yrYH4_M — ELO 858, themes: crushing, deflection, endgame, side to move: White
• Puzzle 01QgT_M — ELO 975, themes: endgame, mate, mateIn2, side to move: Black
• Puzzle zQVCa — ELO 1128, themes: endgame, hookMate, long, side to move: Black
• Puzzle 00Ta0_F — ELO 1178, themes: crushing, endgame, fork, side to move: Black
• Puzzle 007eS_F — ELO 1306, themes: advantage, endgame, short, side to move: Black
• Puzzle zxGvO — ELO 1619, themes: attraction, crushing, deflection, side to move: Black
• Puzzle zwd4v_M — ELO 1758, themes: endgame, epauletteMate, master, side to move: White
• Puzzle zzNGa — ELO 2174, themes: attraction, crushing, endgame, 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).