Chess Opening Theory/1. e4/1...d5/2. d3

= 2. d3 = 2. d3 is a timid reply, usually played only for surprise value or by beginners. After dxe4 3.dxe4 4.Qxd1+ 4.Kxd1, white can't castle anymore. It doesn't put any pressure on black, either. This is never seen in master play.

Theory table
.
 * 1. e4 d5 2. d3