Bird Variation, Paulsen Variation

The Paulsen Variation of Bird's Defense answers 5. O-O with 5...Ne7, developing the knight before the dark-squared bishop. This shuts in the bishop for now, which is why the usual order is 5...Bc5 first. White most often closes the center with 6. d3, while 6. c3 challenges the d4 pawn at once. Black has scored well against 6. c3 in online games. Engines give White a slight edge, and the line is seldom played.