5.P to Kt 55.Kt to R 4
6.Kt takes P6.Kt to R 3 (!)
7.P to Q 47.P to Q 3
8.B takes Kt8.P takes B
9.Kt takes P...
...9.Q to B 3
10.Q to R 5...
...10.Castles (quite legal)
11.Kt takes R P: dble. ch.11.K to Kt 2
12.Kt to Kt 412.B takes Kt
13.Q takes B: ch.13.K to R sq.
14.Q to K 214.B takes P, and wins.

...5.Q P to R 3

Not 5. ... Kt takes P, which would be met by 6. P to R 5, with a winning attack. And not 5. ... P to Q R 4, which is inferior to the text move, and weakens the pawns on the Queen's side for the End game.

6.Castles6.P to Q 3
7.P to B 37.Kt to B 3
8.P to Q 3

The position is now equivalent to the Giuoco Piano, except that White has advanced his Queen's side pawns, which is a slight disadvantage.

THE TWO KNIGHTS' DEFENCE.