A01: Nimzo-Larsen attack: PSCC classification

We consider lines with 1000+ master games in the Local Explorer.

PSCC hierarchy names:

1B+ Nimzo-Larsen hierarchy (NLA)

1BE+ Queen's Indian attack (QIA)

1BG+ Double Fianchetto (DF)

1dg+ King's Indian defense (KID)

2c1B+ English NLA

2d1B+ Classical NLA

2e1B+ Modern NLA

2e1BE+ Modern QIA

2C+ English hierarchy

2C1g+ Great Snake hierarchy

2C1Bg+ NLA Great Snake

2C1BGg+ DF Great Snake

2D+ Queen's Pawn hierarchy (QP)

2D1Gg+ Przepiorka hierarchy

2D1BGdg+ Przepiorka NLA hierarchy

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Longest lines with 1K+ master games:

1. b3 e5 2. Bb2 Nc6 3. e3 Nf6 2e1BE Modern QIA

1. b3 e5 2. Bb2 d6 2e1Bd Modern NLA

1. b3 d5 2. Nf3 Nf6 3. Bb2  2e1B Classical NLA

1. b3 Nf6 2. Nf3 g6 3. g3 Bg7 4. Bb2 O-O 5. Bg2 d6 6. d4 2D1BGdg Przepiorka NLA hierarchy

1. b3 Nf6 2. Nf3 g6 3. g3 Bg7 4. Bb2 O-O 5. c4  2C1BGg DF Great Snake

Przepiorka variation is discussed here :

https://www.chess.com/forum/view/chess-openings/longest-line-of-nla-with-1k-master-games-leads-to-przepiorka-variation