 Its greatest appeal may be that by adopting a set pattern of development, White can avoid the large amount of opening study required to prepare to meet the many different possible Black replies to 1.e4.The English also frequently transposes into a d4 opening, but it can take on independent character as well including symmetrical variations (1.c4 c5) and the Sicilian Defense in reverse (1.c4 e5).With Bird's Opening White tries to get a strong grip on the e5-square.