" 1. d4, d5 2. bf4 " Some sources call this Queen Pawn opening the Sarratt attack and one source said it can even lead to the "London System" One modern day user of this system is Kovacevic (but I need to get it straight as to whether I am speaking about Slobodan, Blazimir or Vladimir).
If you have used this system; it is very interesting to see some of the same "sorts of situations" set themselves up in these Master's games and one's personal uses.
Be careful to imply that C4 leads to the Queen's Gambit; Matthew Sadler in his recent book "The Queen's Gambit Declined" specifically writes that in speaking of the QG, we are speaking of 1. d4 d5 2. c4 for White's second move; not NF3 or some of the other choices out there. Both C3 and C4 have been played in this opening I am analysing.
Concise Chess Openings by McDonald lists the London System on page 285 as "1. d4 Nf6 2. Nf3 g6 3. Bf4 ..."
Updated: Seirawan calls this line in his book on openings, the Mason variation for James Mason; he doesn't regard it as overly strong, but one would need literally the same Trump card he uses in the book against the system. Pun intended; because in other news; the Trompowsky is called the Levitsky variation!
Yasser Seirawan remarks on this opening as a way to respond! And his response is not necessarily perfect; but I found as White, you now have to be very careful as to what your response will be.
1. d4 d5 (by the way, cause the "pros" usually answer with Nf6 to d4, I've found this works decently).
2. Bf4 Bf5
3. e3 e6
4. c4 Bxb1! <---- See that? now White has to play very gingerly!
5. Qa4+ Nc6
6. Rxb1 Bb4+
7. Kd1 Bd6!
Of course, in this situation, why not c3 or Nbd2 by White, avoiding Seirawans assertions. However, what an interesting idea, take the Queen's Knight, before it can have an effect on the Queen, as a sentry on the Queen's side; a lot here.
Update: In a similar situation, this is exactly what Seirawan does in game number 10 of this collection; how odd to see it after writing about this 2 months ago. In the game with Spassky, move 5... Bxb1 (the Knight).
So, a simple underlying theme of the London System would seem to be that if Black plays one of the Indian Defences, whereby wrestling some initiative of the game from being a Queen's Gambit; then, White can indeed, play this against the KID or others; and do the same to Black.
Not yet, released, but at Amazon there is a coming book on the "London System" :