The English Opening is a chess opening that begins with the move: 1. c4 A flank opening, it is the fourth most popular and, according to various databases, one of the four most successful of White's twenty possible first moves. White begins the fight for the centre by staking a claim to the d5-square from the wing, in hypermodern style. Although many lines of the English have a distinct character, the opening is often used as a transpositional device in much the same way as 1.Nf3 – to avoid such highly regarded responses to 1.d4 as the Nimzo-Indian and Grünfeld Defences — and is considered reliable and flexible.