Nf6 3.d4 Bb4, are also feasible. In the Encyclopaedia of Chess Openings scheme, the Nimzo-Indian is classified as E20-E59. This hypermodern opening was developed by Grandmaster Aron Nimzowitsch who introduced it to master-level chess in the early 20th century. Unlike most Indian openings the Nimzo-Indian does not involve an immediate fianchetto