1 d4 Nf6 2 c4 e6 3 Nf3 Bb4+:
A dual-purpose move. Black ensures rapid kingside castling and likely e4 domination.
If the b1 knight jumps to c3/d2, it’s then unable to challenge f6 on e4. If the c1 bishop
covers e1, Black is still solid on e4...
1 d4 Nf6 2 c4 c5 3 d5 b5:
What's the Way Forward White?
* Initially, White needs to decide whether to accept the sacrifice or not.
* If he takes the pawn, Black gets a half open a- and b-file for counterplay.
* White's basic objective is to break through with e4-e5 after proper planning.
However, he also needs to attend to Black's queenside threats, particularly the
intrusion of Black's knights on d3.
* Alternatively, White can refuse the proffered pawn,
in which case Black has only the b-file for counterplay.
* The game plan is still an e4-e5 breakthrough
What's the Way Forward Black?
* Black gains prolonged activity at the expense of a pawn.
* If White accepts the pawn, Black aims to: Move the rook
from f8 to b8, advance the c5 pawn to c4 and then get a
knight on d3 via Nd7-c5 or Nf6-g4/d7-e5.
* The Black queen is normally placed on a5 or b6.
However, sometimes it is set on a8, after the preparatory Ra7.
From these posts, the Queen eyes White's d5 and a2 pawns.
* After positioning all the pieces on their ideal posts,
Black aims for a breakthrough with e7-e6.
If White's pawn is already on e4 sometimes even f7-f5 is
worthy of attention.
BOGO-INDIAN DEFENSE ELECTRONIC-BOOK (E-BOOK):