Amar Opening

The Amar Opening, Paris Opening, Drunken Knight Opening, or Ammonia Opening is a chess opening defined by the move

1. Nh3

This opening is sometimes known as the Ammonia Opening, since NH₃ is the chemical formula for ammonia. The Parisian amateur Charles Amar played it in the 1930s. It was probably named by Tartakower who used both names for this opening, although the chess author Tim Harding has jokingly suggested that "Amar" is an acronym for "Absolutely mad and ridiculous" (Winter 1996, p. 89).

Like the Durkin Opening, white develops a knight to a rim square without having much reason to do so, and such a development is quite awkward. (One of Siegbert Tarrasch's proverbs is "A knight on the rim is dim".) Nevertheless, developing the king's knight prepares kingside castling, and therefore 1.Nh3 is a more common move than 1.Na3. Since 1.Nh3 is considered an irregular opening, it is classified under the A00 code in the Encyclopaedia of Chess Openings.

Black's most common reply is 1...d5 which threatens 2...Bxh3, ruining White's kingside pawn structure. White usually plays 2.g3 to prevent this, and black can then take a grip of the center with 2...e5.