Diakonia wrote:
5... Bd7 was mentioned by Greco as early as 1620, and was revived and popularised by Viktor Korchnoi in the 1970s. Now a main line, the idea behind the move is that since Black usually plays ...Bd7 sooner or later, he plays it right away and waits for White to show his hand.
If White plays 6.a3 in response, modern theory says that Black equalises or is better after 6...f6! The lines are complex, but the main point is that a3 is a wasted move if the black queen is not on b6 and so Black uses the extra tempo to attack the white centre immediately.
a3 f6 Bb5, probably best for black is fe5, what follows is Bxc6 bc6 followed by Bg5 by white ∞
5... Bd7 was mentioned by Greco as early as 1620, and was revived and popularised by Viktor Korchnoi in the 1970s. Now a main line, the idea behind the move is that since Black usually plays ...Bd7 sooner or later, he plays it right away and waits for White to show his hand.
If White plays 6.a3 in response, modern theory says that Black equalises or is better after 6...f6! The lines are complex, but the main point is that a3 is a wasted move if the black queen is not on b6 and so Black uses the extra tempo to attack the white centre immediately.