What is E4?
1.
the most popular opening move in chess where the pawn immediately in front of the king moves two spaces forward.
it immediately gains control of the center and also frees the queen and king's bishop. at the same time, it places a pawn on an undefended square and weakens d4 and f4.
a response of 1...e5 results in an open game.
bobby fischer rated 1. e4 best by test
See
