Originally posted by likeforest
can anyone suggest a definative opening refrence for the GG. i currently looking at: Play 1.D4!
Well, you have to consider that black's going to do much more than play 1...d5 against you - you'll probably see 1...Nf6 two or three times more often.
So breaking things down, against
1...d5 2.c4 dxc4 3.e4 is the aggressive way to play, you have to consider other options though, i.e. 3.Nc3, 3.e3, 3.Nf3. I can't tell you everything about these lines because I don't play 1.d4 but somebody mentioned the QG book by Ward - if you're serious about the KG I'd look that book up on amazon (great prices, best shipping and return policies).
1...d5 2.c4 e6 - Standard Declined, These positions are generally slower, so you may have to search a bit for something sharp if you aren't content with it.
Black can also play the Slav/Semi-Slav which you absolutely MUST be prepared for.
1...Nf6 you can try to avoid the mainlines with the Trompowky (2.Bg5) or you can play the more sound but theory heavy mainlines starting with 2.c4. From here you HAVE to be prepared for the NID, KID, QID, Benko, Grunfeld, Benoni, and wary of stuff like the Budapest Gambit - which can be nasty.
So you'll have to do your fair share of research. You're looking at 1-2 years before mastering a lot of this stuff. Which isn't bad, 1.e4 is about the same. I'd do some book browsing on amazon, and check out GM (recentish...) games with 1.d4.