I'm a Gambiteer... I'm learning the Blackmar-Diemar Gambit...

But what what kind of opening would you recommend if the opponent replies 1.d4 Nf6 instead of 1.d4 d5?

That is overstretching it a bit---and this is coming from someone who isn't particularly fond of gambit play.....

Objectively, yes, gambits like the BDG aren't good. But, they have the potential of putting your opponent in uncomfortable territory where you call the shots, so to speak. Unless, you have a line prepared beforehand, it will be tougher think you think to solve the problems over the board.

Gambits don't suit everyone but they are fun to play for many people--aka gambitlover on this site.

All that being said, against 1.d4 Nf6, maybe you can try 2. Nc3 d5 3. e4 and try to transpose to the BDG (after 3...dxe4). However, Black has the alternate option of 3...Nxe4 that you will have to look at. Or you can play 2.f3 d5 3.e4....

Thanks LavaRook! Hopefully I'll learn how to transpose into my desirable position... :P

I was personally thinking about trying Trompowsky, which is supposed to be a sharp opening, but after seeing the main lines, it doesn't seem very tactical to me...

I too like gambits, and there isn't much wrong with the BDG, i play it too. Unless you are playing at the highest level, your opponent will make the odd mistake or two during the game. It's incredibly difficult to continuously defend accurately when you have pieces pointing from all over the place at your king.

As for your original question, i agree with Lava's suggestions, but suggest also you might like to try e4 for your first move, where there are more opportunities for true gambits. i usually only encounter the BDG when black plays d5. after i play 2.d4, i often find black transposes to french or caro-kann

I'm not at all a fan of this opening, i'll never play the BDG. But your statement is ridicolous. Noone ever considered the BDG to be so bad, so it's not like you're not up with the theory, your idea is just totally wrong. First of all it takes e real effort to look at white idea and say that white is not going to have some compensation. It's clear that white has something for his pawn. The question is whether it's enough. 

The answer according to current theory is that white can reach rough equality in all lines(even if sometimes he is really the one fighting for equality, so in this sense yes, thr BDG is not a great opening). The only line (4...c6) in which (serious) people was claiming =+ (please note, a slight edge for black, nothing more) has been supposedly repaired by GM Gutman  in this article http://www.chesscafe.com/text/kaiss42.pdf. So instead of making bold statements without providing a single move, maybe you can look for an improvement for black. Or post your supposed alternative "refutation."

Back to the original question, one of the issues with the BDG is that you can't play it against 1...Nf6. 2.f3 c5 leads to positions where the pawn on f3 is just silly, while 2.Nc3 Nf6 3.e4 Nxe4! is also considered advantageous for black (but there is little experience here, so the last word has not been said).

Why not? some of the sharpest sacrifical lines in the whole game of chess stem from the queen's gambit. Just think about all the slav structures where white gives away a pawn for a huge centre and attacking chances. Many 1.e4 gambits look anemic in comparison.

It's funny how people think that 1.e4=sharp and 1.d4=dull. It's not WHAT you play it's HOW you play. Karpov, a positional player, favoured 1.e4 for a long time before swtiching to 1.d4. Kasparov, an aggressive player favoured 1.d4. 

There is no really good way around learning how to deal with other openings than your ideal responses. But the plus side is that you'll be a better chessplayer for having a broader understanding of more than a few pet lines.

Some play chess for fun ... and playing the BDG is often a LOT of fun ... besides, you get a lot of practice trying to salvage a draw when down a pawn (or more).

1. ... Nf6, btw, signals the Hubsch Gambit if White insists (or a transition back to the BDG if Black allows it) on continuing in gambit fashion. Not nearly as much fun as the BDG, but one cannot always play what one wants to most.

Truly brave gambiteers try the Soller Gambit with Black.

Good move (i guess you mean 1.d4 Nf6 2.Nf3) but it's not what the average BDG player likes i fear. I mean, it's foundamentally an attempt to play the queen gambit (with a later c4) while avoining the sharpest counters. A solid move.

Actually, the Hubsch is 1.d4 Nf6 2.Nc3 d5 3.e4 Nxe4, I believe.

DrawMaster, i was answering to post 16 :)

Yes, the Hubsch is that line.

Just a few additions to the conversation:

When I play the BDG, it's a helluva fun game.  With all gambits of questionable soundness, it may not be the best but it is certainly not an immediate loss like a previous poster said.  Someone did say that with this gambit it does require precise play, and I would agree to that in certain lines.  Once you play the BDG OTB or even on the internet, you will start to realize that a lot of people absolutely do not like playing the BDG as black and will transpose to the french or caro kann.

To your other question, how to handle 1...Nf6.  after 2. Nc3 and 2...d5 you can push the e-pawn and it may bring you into a BDG game, however, it could also go hubsch.  Hubsch is not fun, not near as open, and you really do feel like you are playing catch-up. I tried hard to like it, but it just isn't fun at all and it always ends in a game that I hated playing.

My reccomendation is to play the veresov:

1.d4 1...nf6 2.Nc3 2...d5 3. Bg5

This is a much better game than the hubsch.  Trust me, I'm a big BDG player and Hubsch is not the way to go. 

 +1 from an aggressive d4 player. Spot on. Even the London System can be very attacking if played as such. If you don't believe me, look up GM Vlatko Kovacevik in chessbase.

Well, it's almost impossible to find a second move for white which is so bad that he is seriously worse. Yes white is "ok", he has very good equalizing chances, but wasting your natural slight edge and handling it right away to black without even posing him problems it's hardly something to write home about ;)

Specifically, i wonder how is white going to make Qd3 an useful extra move in the reversed chigorin that arises after 3...c5. And this is just one of the many possible defences. It's not black which has to prove Qd3 bad, it's white that has to show what the idea behind Qd3 is. A line where such an early queen move occours is 1.d4 d5 2.Nc3 Nf3 3.Bg5 Nd7 4.Qd3!? which is respectable, with the idea of organizing O-O-O and e4 as quick as possible. But on move 2 looks really premature. The queen might easily be a target (b6-Ba6 might be an idea) and white has more natural ways to suppport e4. 

Computer-wise, there's nothing wrong with this move... But it violates the basic principles of good opening development, which is to move all your minor pieces into position first, and the queen should be centralized last...

However, keep in mind that for many years the Scandinavian defence was also laughed at because it violated those principles.