Chess concepts — 4,505 SAE-derived patterns

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4,505 interpretable chess concepts extracted via sparse autoencoders on Leela Chess Zero's residual stream. Each was labelled by reading top-activating positions. Below: the 30 most common patterns by puzzle coverage. Click any concept for a dedicated page with its full label, statistics, related concepts (Jaccard-similar), and example puzzles spanning the rating range.

Top 30 concepts by puzzle coverage

  1. sae_3802 — White Queen on the 1st or 2nd rank, unthreatened by black and defended by at least one… (6,134 puzzles)
  2. sae_2234 — A queen actively placed on an open rank or file relative to the enemy king, creating… (5,368 puzzles)
  3. sae_1449 — Detects white king safely castled on the back rank (typically b1 or g1) in middlegame… (4,511 puzzles)
  4. sae_4199 — A black queen on a central or open file, not attacked by white pieces, with at least one… (4,317 puzzles)
  5. sae_19898 — Detects a king on the target square that is not attacked by the opponent, especially… (3,950 puzzles)
  6. sae_27871 — This feature detects a white queen on a square where it is not attacked by black pieces… (3,771 puzzles)
  7. sae_10213 — Black king in a late endgame, frequently near the back rank or in a cornered/restricted… (3,304 puzzles)
  8. sae_8592 — A black bishop that is active or under pressure in a tactical position, often near the… (2,418 puzzles)
  9. sae_27762 — White King near a corner square (a1, h1, a2, h2) in an endgame or mating-net position. (2,362 puzzles)
  10. sae_2076 — A king on the back rank exposed to at least one enemy attacker with no friendly piece… (2,330 puzzles)
  11. sae_2631 — Detects kings in near-opposition or close proximity in simplified endgames (pawn, rook… (2,121 puzzles)
  12. sae_23934 — Detects a king on a square with few (0-2) friendly defenders and no enemy attackers… (1,813 puzzles)
  13. sae_1354 — A black knight active in enemy territory, often participating in a mating combination or… (1,548 puzzles)
  14. sae_2049 — King actively centralised in a late endgame (pawn or minor piece), not constrained to a… (1,543 puzzles)
  15. sae_10458 — Detects an early-development black position where the queen remains near the back rank… (1,521 puzzles)
  16. sae_1774 — An uncastled rook on the back rank that retains castling rights, with no immediate… (1,255 puzzles)
  17. sae_12239 — White bishop on home territory (ranks 1-3) in a standard development position… (1,204 puzzles)
  18. sae_28176 — A king in a vulnerable position, typically on or near the back rank, with limited… (1,159 puzzles)
  19. sae_18409 — Active knight participating in a mating attack, often with king exposed and supporting… (1,135 puzzles)
  20. sae_5208 — King in an endgame position with no immediate threats, spanning pure pawn endings, rook… (1,089 puzzles)
  21. sae_9371 — Rook operating on an open file or rank as the key piece in a mating attack or decisive… (1,069 puzzles)
  22. sae_18888 — Detects a queen on the home-side back ranks (1st–2nd for white, 7th–8th for black) that… (1,010 puzzles)
  23. sae_355 — Detects a knight posted on a central or near-central square (c3–f5 region) that is under… (991 puzzles)
  24. sae_953 — White king on the back rank (e1–g1 area) in a tactical position with active white pieces… (966 puzzles)
  25. sae_2002 — A well-supported white knight on an outpost square that is contested by black. (960 puzzles)
  26. sae_19500 — A white knight on a stable central or near-central square, participating in an attack or… (897 puzzles)
  27. sae_7263 — White queen actively placed in a central or tactical role, defended by at least one… (896 puzzles)
  28. sae_3679 — Black king on g8 or f8, sheltered by kingside pawns, in a middlegame or endgame tactical… (876 puzzles)
  29. sae_2769 — Active king in a king-and-pawn endgame, often on the 3rd–5th rank with adjacent pawns… (865 puzzles)
  30. sae_13581 — A black knight posted on a central or semi-central square (c4–f5 region), regardless of… (772 puzzles)