The Neo-Indian Attack is a chess opening

Chess opening

A chess opening is the group of initial moves of a chess game. Recognized sequences of opening moves are referred to as openings as initiated by White or defenses, as created in reply by Black. There are many dozens of different openings, and hundreds of named variants. The Oxford Companion to...

 defined by the opening moves
1.d4 Nf6 2.c4 e6 3.Bg5.
This opening is also known as the Seirawan attack, after top 1980s player Yasser Seirawan.

The pin

Pin (chess)

In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

ning of the f6 knight

Knight (chess)

The knight is a piece in the game of chess, representing a knight . It is normally represented by a horse's head and neck. Each player starts with two knights, which begin on the row closest to the player, one square from the corner...

 looks similar to the Torre Attack

Torre Attack

The Torre Attack is a chess opening characterized by the moves:The opening is named after the Mexican grandmaster Carlos Torre Repetto. The variation was also employed by Savielly Tartakower, and the young Tigran Petrosian on occasion...

, but while the Torre is fairly common, the Neo-Indian is rarely played. The move order has been used by players such as David Janowski against Edward Lasker

Edward Lasker

Edward Lasker was a leading German-American chess and Go player. He was awarded the title of International Master of chess by FIDE. Lasker was an engineer by profession, and an author.-Background:...

 in New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 1922. The opening has been considered possible opening surprise in the Secrets of Opening Surprises series.

The most common responses from Black are

• 3...h6 which forces the bishop to move again, and unlike the Trompowski Attack
  Trompowski Attack
  The Trompowsky Attack is a chess opening that begins with the moves:With his second move, White intends to exchange his bishop for Black's knight, inflicting doubled pawns upon Black in the process. This is not a lethal threat; Black can choose to fall in with White's plan.The Trompowsky is a...
  
  , 4.Bxf6 will not leave Black with doubled pawns
  Doubled pawns
  In chess, doubled pawns are two pawns of the same color residing on the same file. Pawns can become doubled only when one pawn captures onto a file on which another friendly pawn resides. In the diagram, the pawns on the b-file and e-file are doubled...
  
  .
• 3...Bb4+ which can transpose to the Leningrad variation of the Nimzo-Indian Defense after 4.Nc3 or lead to unique variations after 4.Nd2.

Unless the game transposes to another variation, the Neo-Indian is classified as E00 by the Encyclopaedia of Chess Openings

Encyclopaedia of Chess Openings

The Encyclopaedia of Chess Openings is a classification system for the opening moves in a game of chess. It is presented as a five volume book collection describing chess openings...

.