PSCC Classification of openings with 1000+ master games

Well, I'm working on classification of openings by Pawn Structure Classification Codes, cf. my blog: https://www.chess.com/blog/Yigor/pawn-structure-classification-codes

Here is the very beginning of this classification for openings with 1000+ master games in the Opening Explorer.

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By definition, an opening is Hippo (for white / black) when the height of any pawn is less or equal to 1 with respect to the Initial Pawn Structure.

PSCC (Pawn Structures Classification Codes): 1b, 1d, 1e, 1g, 1B, 1D, 1E, 1G, 1Bg, 1Gb, 1Ge, 1Gg, 1Gbe, 1BGg, 1DGg, 1BGdg

Initial / Initial (height 0 = 0+0)

1. Nf3 Réti

1. Nf3 Nf6 Réti: Symmetrical

1. Nf3 Nc6 Black Mustang

1. Nc3 van Geet

Initial / Hippo (height 1 = 0+1)

1b 1. Nf3 b6 Réti: QF

1d 1. Nf3 d6 Réti: Pirc Invitation

1e 1. Nf3 e6 Réti: QG Invitation

1g 1. Nf3 g6 Réti: KF

Hippo / Initial (height 1 = 1+0)

1B 1. b3 Nimzo-Larsen attack / 1. Nf3 Nf6 2. b3 Réti: Nimzo-Larsen attack

1D 1. d3 Mieses

1E 1. e3 van't Kruijs

1G 1. g3 Benko / 1. Nf3 Nf6 2. g3 King's Indian Attack

Hippo / Hippo (height 2 = 1+1)

1Bg 1. b3 Nf6 2. Nf3 g6 3. Bb2 Bg7 Nimzo-Larsen Attack

1Gb 1. Nf3 Nf6 2. g3 b6 3. Bg2 Bb7 4. O-O King's Indian Attack

1Ge 1. Nf3 Nf6 2. g3 e6 3. Bg2  King's Indian Attack

1Gg 1. Nf3 Nf6 2. g3 g6 3. Bg2 Bg7 4. O-O O-O KIA: Symmetrical

Hippo / Hippo (height 3 = 1+2)

1Gbe 1. Nf3 Nf6 2. g3 b6 3. Bg2 Bb7 4. O-O e6 KIA vs QID

Hippo / Hippo (height 3 = 2+1)

1BGg 1. Nf3 Nf6 2. g3 g6 3. b3 Double Fianchetto

1DGg 1. Nf3 Nf6 2. g3 g6 3. Bg2 Bg7 4. O-O O-O 5. d3 Modern Attack vs KID

Hippo / Hippo (height 4 = 2+2)

1BGdg 1. Nf3 Nf6 2. g3 g6 3. b3 Bg7 4. Bb2 O-O 5. Bg2 d6 Double Fianchetto vs KID

I'll continue my PSCC classification with Normal openings up to height 4 (and 1000+ master games).

Hippo / Normal (height 0 = 0+2)

2c 1. Nf3 c5 Réti: Sicilian or 1. Nc3 c5 van Geet: Sicilian

2d 1. Nf3 d5 Réti: QP or 1. Nc3 d5 van Geet: QP

2f 1. Nf3 f5 Réti: Dutch

Flank / Initial (height 2 = 2+0)

2B 1. b4 Sokolsky

Normal / Hippo (height 2 = 2+0)

2C 1. c4 English Nf6 Anglo-Indian 2. Nf3 Anglo-Indian: KK or 2. Nc3 Anglo-Indian: QK

2D 1. d4 QP 1...Nf6 Indian 2. Nf3 Indian: KK or 2. Nc3 Indian: QK or 2. Bf4

     1. d4 Nf6 2. Bg5 Trompowsky Attack 2...Ne4 3. Bf4

White can play 3. Bf4 or 3. Bh4, but the first option is more popular.

U wasted all your time for this nonsense?

This is not hippo openings...

Another try?

+1 lol

It's my free time. What have U achieved except for trolling other participants here during several years ?!?

N.B. I just started with Hippo (in the sense that I have defined) and now continue in the same thread.

Normal / Hippo (height 2 = 2+0)

2E 1. e4 Nf6 Alekhine defense 2. Nc3 --> 2Ed, 2Ee

     1. e4 Nc6 Nimzo defense 2. Nf3 --> 2E1d, 2Ee

2F 1. f4 Bird's 1...Nf6 2. Nf3 --> 2Fd

Hippo / Flank (height 3 = 1+2)

2b1G 1. Nf3 Nf6 2. g3 King's Indian attack 2...b5 KIA: Spassky variation 3.Bg2 Bb7 4. O-O --> 2b1Ge

Hippo / Normal (height 3 = 1+2)

2c1G 1. Nf3 Nf6 2. g3 King's Indian attack 2...c5 KIA: Sicilian 3. Bg2 Nc6 --> 2Cc1G

2d1B 1. b3 Nimzo-Larsen Attack 1...d5 NLA: Classical 2. Nf3 Nf6 3. Bb2

2d1G 1. Nf3 Nf6 2. g3 King's Indian attack 2...d5 KIA: Yugoslav variation 3. Bg2 Bf5 or 3...Bg4

2e1B 1. b3 Nimzo-Larsen Attack 1...e5 NLA: Modern 2. Bb2 Nc6 --> 2d1BE

I distinguish between Initial (with initial pawn structure), Hippo, Flank and Normal openings for white and black. Advance and other types will appear later with higher heights.

Some remarkable opening hierarchies:

1B+ Nimzo-Larsen hierarchy

1G+ KIA hierarchy

2C+ English hierarchy

2D+ QP hierarchy

2E+ KP hierarchy

2F+ Bird's hierarchy

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Abbreviations:

KIA = King's Indian Attack

KID = King's Indian Defense

KK = King's Knight

KP = King's Pawn

NLA = Nimzo-Larsen Attack

QID = Queen's Indian Defense

QK = Queen's Knight

QP = Queen's Pawn

Trolling?

I just try to be informative/educational.

Sometimes i give advice, sometimes i just tell that someone tells wrong thing (like almost all u give here), sometimes i am kidding...

U give bad informations : u have the right to use wrong things, but please, don't share them and keep it for you. U could misguide some persons here. If only u could learn but u stay with your ignorance.

How opening classification codes (based on pawn structures) could be bad / misleading ?!?

Hippo opening has nothing to do with what u give.

It's just a terminology, I call Hippo any opening where pawns don't move farther than 1 square from the initial position. Imho it's quite clear and natural. Suggest a better name if U have one.

Hippo is already a well established opening so u can't use again the same name for another thing.

Maybe the "Inno" , like innocuous? Or more seriously the Rhino, or even the Yigo?

Wikipedia: The Hippopotamus Defence is a name for various irregular chess opening systems in which Black moves a number of pawns to the sixth rank, often developing pieces to the seventh rank, and does not move any pawns to the fifth rank in the opening.

This is fully consistent with my definition!

Normal / Hippo (height 3 = 2+1)

2C+ English hierarchy

2C1b 1. c4 English 1...Nf6 Anglo-Indian 2. Nf3 b6 --> QID

2C1c 1. c4 English 1...Nf6 Anglo-Indian 2. Nf3 c6 3. Nc3 --> Caro-Kann

2C1d 1. c4 English 1...Nf6 Anglo-Indian 2. Nf3 d6  --> Old Indian

2C1e 1. c4 English 1...Nf6 Anglo-Indian 2. Nf3 e6 3. Nc3 Bb4 Nimzo-English 4. Qc2 O-O

2C1g 1. c4 English 1...g6 Great Snake 2. Nc3 Nf6 3. Nf3 Bg7 --> KID

Normal / Hippo (height 3 = 2+1)

2D+ QP hierarchy

2D1b 1. d4 QP 1...b6 English defense --> 2DE1b English/Owen defense

          1. d4 QP 1...Nf6 Indian 2. Nf3 b6 --> QID

2D1c 1. d4 QP 1...c6 --> 2DE1c Caro-Kann

2D1d 1. d4 QP 1...d6 2. Nf3 Tartakower variation 2...Nf6 Tartakower defense

              --> 2CD1d Old Indian (with Nf3)

          1. d4 QP 1...d6 2. Nf3 Tartakower variation 2...Bg4 Wade defense

2D1e 1. d4 QP 1...e6 Horwitz defense 2. Nf3 Nf6 3. Bf4 London system

          1. d4 QP 1...e6 Horwitz defense 2. Nf3 Nf6 3. Bg5 Torre attack

          1. d4 QP 1...Nf6 Indian 2. Bg5 Trompowsky attack e6 3. Bg5 Torre attack

          1. d4 QP 1...Nf6 Indian 2. Bg5 Trompowsky 2...e6 Trompowsky: Classical defense 3. Nd2

2D1g 1. d4 QP 1...Nf6 Indian 2. Nf3 g6 East Indian 3. Bg5 Torre attack 3...Bg7 Torre:

              Fianchetto defense 4. Nbd2 O-O

2D1g 1. d4 QP 1...Nf6 Indian 2. Nf3 g6 East Indian 3. Bf4 London system 3...Bg7

          1. d4 QP 1...Nf6 Indian 2. Nf3 g6 East Indian 3. Nc3 --> 2Dd1g QPG: Chigorin or 3. Nbd2

2D+ QP hierarchy

2D1d Tartakower-Wade pawn structure leads to Tartakower defense, Wade defense as well as to Old Indian.

2D1e Horwitz pawn structure leads to London system and Torre attack.

Normal / Hippo (height 3 = 2+1)

2E+   KP hierarchy

2E1b 1. e4 KP 1...b6 Owen defense --> 2DE1b

2E1c 1. e4 KP 1...c6 Caro-Kann 2. Nc3 or 2. Nf3 --> 2Ed1c

2E1d 1. e4 KP 1...d6 Pirc defense 2. Nc3 Nf6 --> 2DE1d

2E1d 1. e4 KP 1...Nc6 Nimzo defense 2. Nf3 Nimzo declined 2...d6 Nimzo declined:

              Williams variation --> 2DE1d

2E1e 1. e4 KP 1...e6 French defense 2. Nf3 French: KK --> 2Ec1e Franco-Sicilian hierarchy

2E1e 1. e4 KP 1...e6 French defense 2. Qe2 French: Chigorin variation --> 2Ec1e

2E1e 1. e4 KP 1...e6 French defense 2. Nc3 French: QK --> 2Ec1e

2E1g 1. e4 KP 1...g6 Modern defense 2. Nf3 --> 2Ec1g Hyperaccelerated Dragon

2E1g 1. e4 KP 1...g6 Modern defense 2. Nf3 Bg7 --> 2DE1g

Some interesting hierarchies:

2C1g+ Great Snake

2E1e+ French hierarchy

2Ec1e+ Franco-Sicilian

2Ec1g+ Hyperaccelerated Dragon

Example: French --> Franco-Sicilian transition :

Advance / Initial (height 3 = 3+0)

3E+    Alekhine hierarchy

3E 1. e4 KP 1...Nf6 Alekhine defense 2. e5 Nd5 Alekhine: Normal variation

We have finished with PSCC codes for openings with pawn height less or equal to 3 and 1000+ master games in the Local Explorer.