1. d4 Nf6 2. d5?

I played against this in an OTB game, I had no clue how to play against it...

I played this against it, and later went on to win.

and stuff continued from there...

But my question is, what is the proper way to respond to this? What is the best way?

e6 looks good just to challenge it right away. of course if dxe6, fxe6 and black has a nice center so. probably end up in some sort of benoni position except without c5 black probably has more piece flexibility.

Id play 2.c5 then b5 if c4 came since I play benko

Also you could try e6 attacking the pawn, then c4 c5 and you have a modern benoni.

Looks like you play KID, so maybe 2..d6 3.c4 3.e5 if dxe6 bxe6 and I like the position

Transpose to a benoni (by c5 at an early point) if you play that. If not, play c6 to undermine the white centre. If he takes, you'll take back with the b-pawn, advance in the centre and gain a dangerous initiative. If he doesn't take, and defend with moves such as e4 and c4, you should play a6-b5, undermining the pawn chain. And the long diagonal for you DSB is very usefull in this attack on the queenside.

transposing to a benoni gives white exactly what he wants.. c5 is not an ideal move, blocking in the dark square bishop and more or less forcing an extra tempo to be wasted with g6 to get it developed. 

I prefer g6, 1 move is not so important in this closed position, and black should definetly get equality:

Speaking of 365chess.com I looked at one line that went:

1. d4 Nf6 2. d5 d6 3. c4 e5 4. Nc3 Be7 5. e4 0-0 6. Bd3 c6 7. Nge2 Nbd7 8. 0-0 Nc5 9. Bc2 cxd5 10. cxd5 a5 and of the possible replies:

11. f3 1/2-1/2

11. Be3 1-0

11. Ng3 0-1

11. a4 1-0

The database lists it as A45: Queen's pawn game. However, if you look at the moves f3 is called the Old Indian, Ukranian variation (A54), Be3 and Ng3 list it as the simply the Old Indian (A53) while a4 is listed as the King's pawn game (B00). All the games listed go back to between 1997 and like 2004 with players as high as 2300 FIDE playing.

1. d4  Nf6  2. d5?? is a terrible move and violates the rule not to move a pawn twice in the opening without a good reason.  The corredt response is 2. ...c6

Great listings of positions ponz, especiall if someone is a good positional or attacking player.

LOL I played this after coming back after a 25 year break simply because it takes all the Indian players out of book on move 2 :)

Ideally you are aiming to set up a pawn centre with f3-e4

The variation posted above is probably black's best line but it's still  playable for white. 2 Nc3 for White is probably better than c4.

Excession moving a pawn twice without a good reason is a fundamental mistake in the opening.

If Black attacks the pawn with 2. ...c6 then White has already lost his opening move advantage.  Not only that but Black then has a slight advantage. 

Would not classify this senario as "playable" unless "playable" means throwing away a slight plus to obtain a slight minus!

Oh, I don't mean that it's recommended or optimal in any way, just that the position is playable for White, in that Black has no forced way to win material. Obviously Black is very comfortable if he can find that variation over the board.

I almost swear your opponent was on my chess team in HS

Oh sure but after 25 years out of the game entirely I would just have got slaughtered trying to remember playable lines vs the various Indian defenses.

It did the job in terms of coming out of the opening (more or less equal) on position and time. You'd be surprised how many people panicked and end up playing a Benoni without knowing what to do or even just let me set up a nice pawn chain with f3-e4.

I could equally well have chosen the Catalan, Reti or Bird's opening I guess but they all contain more theory and I just wanted out of book fast.

Besides, as lot of the time it ended up with 1...d5 and going into the Slav or QGA or QGD, where which I could still just about remember what to do.

It obviously sucks on any objective test for the reasons and lines given above though...

That's one of the beautiful things about chess: with all the available information we have, we get to sometimes discard old ideas and theory for new ones. This might have been a great opening for Black in perhaps the 1920s but after 80 years, there are likely better ways to punish White for violating opening principles.

Still, I see a lot of systems played between begining and intermediate players that some get wins with for nothing more than the other side is thrown off by something. The problem with this is, once these players face poeple whose ideas are sound, they find themselves on the other side of the coin. Then unless they start studying over their losses or learn new ways that are sound, they just get stuck in a habitual rut.

An exmaple I can think of from my own games was when I would play c5 as White in the Semi-Slav. Alot of times, my opponents would fight over the Queen side instead of battling for the center or play on the King's wing. I got plenty of wins and even a draw against an 1800 player.

Suddenly, I was getting players who would play e5, even if the had played e6 prior, weakening my pawn chain from the outset. I came across the c5 advance after reading how Kasparov played it in bahrain against Deep Fritz, getting a draw.

Then, hicuntec posted a link for me showing that e5 was one of Kasparov's favorite ways to counter the c5 advance.

I dropped the Chamaeleon Variation shortly after that.

Sounds a bit crazy perhaps? If it was not true, why do we see many players playing the Parham (oops  said a dirty word) or 2. Bc4 in the sicilian so much?

Nice to see IM pfren back in the postings again.