Clearing the King's side for castling, and posting the Bishop ready for attacking the present weakest point in Black's position—viz., the K B P; weakest because defended by the King only.

...3.B to B 4

No immediate danger being apprehended, Black brings a piece into play. These three moves on either side constitute the opening called the Giuoco Piano, whatever be the moves that may follow.

4.P to Q 34.P to Q 3
5.B to Q 35.B to Kt 3

Better than 5. ... B takes B, because in that case White would obtain an "open Bishop's file," and double his Rooks upon it after castling; and the "double pawn," which is in the majority of positions a weakness, is strong in the centre.

6.Q Kt to Q 2...

The object being to play this Knight to K B sq., and then to Kt 3. This could also be done if White had played 6. Kt to B 3, then Kt to K 2, and Kt to Kt 3. The manœuvre in the text is generally adopted, because if 6. Kt to B 3, Black could "pin" it with 6. ... B to R 4.

...6.Kt to B 3
7.P to B 3...

Intending to advance the Q P, and thus prepare the formation of a strong centre.