The purpose of the English Opening (Part I)
Let's say you are White and a 1.d4 player
But your opponent specializes in the Grunfeld Defense
It is better to play the English Opening instead...
Since you can make it impossible for Black to play the Grunfeld
And force him into a defense he has no idea how to play
To do this... instead of starting the game with 1.d4 start with 1.c4
And if Black plays the starting moves of the Grunfeld
You put your knight here to support the e4 square
When Black plays the second move of the Grunfeld...
Now we place our King pawn here!
Now Black can’t play the next Grunfeld move (we just take pawn)
Black is forced to play this move instead...
Now Black is in a King’s Indian
(Where the strategy is completely different than a Grunfeld...)