Heading for d3 in order to fight for the d-file. Besides this, the rook can also be used in a kingside attack.
In order to double the rooks on the e-file, where Black has a problem with the unstable bishop on e6, as well as with the e6-square itself.
An excellent strike based on the line: 8...hxg5? 9.hxg5 cxd4 10.Qd3! with a winning attack. After 8 Ng5! White enjoys a clear initiative and later won the game.
Clearing the e-file for the rook, in order to enhance an attack on Black's weakened kingside.