The Ware Opening or Meadow Hay Opening, is an uncommon chess opening in which White opens with 1.a4 it is named after US chess player Preston Ware, who often played uncommon openings. Because it is considered an irregular opening it is classified under the A00 code in the ECO (Encyclopedia of Chess Openings)
The Ware Opening attacks the b5 square and threatens to develop the a1 rook to the game. The b5 is not an essential key square in this position and if Black plays 1...e5 the f8 bishop prevents the development of the white rook. The reply 1...e5 also gains occuptation of key central squares, something that is vital for a strong position. Note that the Ware opening fails to make use of White's advantage in time and initiative with the first move and does not seek to occupy this area.
Usually the reply to 1...d5 or 1...e5 would be 1.d4 or 1.e4 respectively with 1...e5 allowing the option of a reversed Scandinavian.
The highly impractical named variations:
1.a4 e5 2.h4 The Crab variation.
1.a4 b5 2.axb5 Bb7 The Wing Gambit.
1.a4 b6 2.d4 d5 3.Nc3 Nd7 The Cologne Gambit.
1.a4 e5 2.a5 d5 3.e5 f5 4.a6 The Ware Gambit.
1.a4 a5 The Symmetric variation