Best Replies for d4 as black

I've seen it used quite a few times. Nakamura, Aronian, Kramnik, Topalov, Caruana, Giri, Ivanchuk, Gelfand have all used it at the Super-GM level . . . Don't forget Gashimov as well, who played it quite often. And of course Tal, as was already mentioned. Polgar played it, too.

Plus, both Fischer and Kasparov wielded it from time to time. In the Kasparov game below, Korchnoi tries your recommendation (a4 and nc4). As we can see, it didn't go well for him.

People often think, that they should play one particular opening, because that is the best opening. In at least that case 80% of the players would play that opening . You should just play an opening which suits you. That is the most important!! Just decide what kind of positions you like and on which points you want to improve as a chess player. But I think it is a myth, that there is one opening which is best. And those very tiny details are only important for people above 2600 rating, but even for them it does not matter much. Otherwise all top players would be playing that opening. Also I find it very ironic that people want to get an edge as white and black. Which is quite controversial in my opinion. 

This being said I hope you will find a good opening against D5 which suits you. A good opening will not help you if it does not fit you. I am quite an aggressive player, which is why I like to play the Dutch. But for someone who likes to play solid positions I would not recommend it. 

Good luck!

This is a very valid point. In general, you should not spend too much time on openings anyways if you're still accumulating rating points rather quickly. Practical ways to tackle openings you're facing (e.g. Google the term SOS) are more useful than always trying to play "optimal" or "best" openings.

I also strongly believe that while you're still learning it may be greatly beneficial to play a wide range of openings to develop and discover your personal favored and disfavored positions. From thereon you can shape your opening repertoire.

The problem is many players do not know what type of positions they are best in because they have never done a survey looking at the data in a scientific way, analyzing their games of open, semi open or closed positions, whether they came out of the opening with an advantage, an equal or detrimental position. I think knowing this would be invaluable because you would then be in a position to choose lines that you can enter into giving you positions in which you feel relatively comfortable, have some idea of planning and strategic aims.  

Wow in both of your games black won because white made some terrible moves. I suggest you to do what i did. Look at the games before posting them and try to understand who was better at which point and try to find improvements to the players play. What you can then do like me is take your engine and check the games. You will see that black was near lost in both games which means his play was NOT sound. That means you can not use these games as arguments that speak for the benoni. Agreed?

Also in earlier ages like in Tals or Fischers chess was not like it is today. Engines are now more relevant ;). The play and the opening lines have become more sound since then.

Another point is of course that all these modern players you listed do not play the Benoni mainly. As I said they play it once in a while because noone really prepares for this opening. In high level chess it is important to not allow your opponent to be fully homeprepared for your opening. Agreed?

The mistake I made earlier, just take openings  from high rated players which won a game. Then I played it, got it outplayed and played another opening. I just did not get the ideas in the opening I was playing. Of course someone beats the crap out of you, who does know his plans. This is the most important in playing an opening, getting the ideas behind it. Well at least for a beginner.

Also the person who asked this question, I have not heard him answer on his own topic. Which is a bit weird because there are already more than 50 posts, which go deeply into his question.

Slav Defense

Naturally, in any game where one side wins, it happens because the other side has made mistakes. Otherwise, with perfect play from both sides, the game will always end in a draw.

Arguing that "black made mistakes in the game, which means his play was not sound, which further means that the Benoni Defense is not sound!" is a bit of a silly argument, to me. I can point to games in the Queen's Gambit where white has made mistakes, and similarly conclude that this means the Queen's Gambit is not sound. See the problem with that kind of logic?

I do agree with you that chess has evolved since the era of Tal and Fischer. Definitely. And yes, a lot of players consider the Benoni to be quite risky for black. With that, I agree with you as well. Though if we ask Caruana about the Benoni—currently #4 in the world—he'd probably tell you that white seems to avoid playing against the Benoni, too.

During the Candidates, after his fighting draw against Aronian, Caruana said, “I wanted to play the Benoni since last two months, but none of my opponents were allowing me to do so."

If one of the strongest modern players in the world wanted to play the black side of the Benoni, in the World Championship Qualifier, it surely can't be that bad of an opening.

Lastly, you can't just "surprise" a White player with the Benoni Defense, in hopes of taking them out of their home prep. That's now how it works. White has to willingly push d5 in order to enter a Benoni structure. It's White's choice whether the game becomes a Benoni game or not.

In conclusion: is the Benoni unsound? Clearly, you believe it is, but I haven't found any compelling evidence to make me agree.

At the highest level of human play (2700+), the Benoni scored 100% draws in 2016, according to my research. I haven't seen it played yet this year, but I'm sure we will.

I do agree that Black often seems to have the more difficult game—but a lot of players enjoy that kind of struggle. In that regard, it's a lot like the French.

I have not seen the sicilian played a lot in 1. D4, but that might be my lack of theoryknowledge. And also the petrov defense, I have not seen yet after 1. D4. Anyone disagrees?

i haven't seen it much either very strange. after e4 yes but that's obviously just a coincidence. 

i hope Syafiq2001GM notices his mistake.

I prefer the nimzo and bogo indian. very straight forward and great endgame practice. I recommend watching chessexplained on youtube. He plays them both very well.

Play a lot of different chess openings over the years and find out what opening type you like. After that specialize on some of them and dive deeply into the chess openings you have selected. When you make a mistake then analyze these mistakes after the game at home and understand what went wrong. In the next games play the same opening lines and avoid the mistakes you have made before. This process goes over years to come. You will find, as your understanding deepens, you get better and better. Of course you never stop analyzing as even in your special openings learning never ends as your opponends vary moves and choose different lines.

There's really no "best" reply that suits everyone just as a shirt that very well-made will not fit everyone. It comes down to what suits your style.

As I mentioned on the 1e4 thread, for 1 d4, 1 c4, or 1 e4, I like 1...c6, usually followed by 2..d5.  That usually puts me in some variation of the Slav Defense or Caro-Kann Defense where I'm very familiar with the ideas behind the openings, familiar with the general positions reached, know where White tends to be weak and what plans and tactics to consider.

This may not be best for those who don't do well in closed positions: White can turn them into wide-open games by playing exchange variations or keep it closed, often with advance variations.