6. ...Nbd6 or 6. ...e6 in the Najdorf?

Nbd7 is rarer and scores better. But I'm not sure I understand the plans or where I can learn it. Does anyone have any ideas?

You are over 2300 rapid, so I'm a bit surprised that you are puzzled on my 6 by a mainline opening. Keep in mind that I'm a d4 player (but I know some Sicilian theory as my chess coach plays the Najdorf), but you should probably specify which 6th move white is playing. I assume you mean 6. Bg5 (the old Russian mainline) when 6...Nbd7 and 6...e6 are the top two moves the engine gives.

6. Be3 English Attack (or the related 6. f3) are what I typically play in off-hand games, but the top moves for black give more options.

Anyhow, back to the 6. Bg5 continuation, I would think ...e6 is more common for the simple fact that black may not be ready to commit the knight to d7 or c6, whereas committing the pawn to e6 is less serious as players wanting to play ...e5 in one move would just do so. I wouldn't be choosing your opening repertoire choice on a smidge of how often people play worse from it because better players are less likely to play worse. In this case, both moves are solid, so I would experiment with both and see which you like more.

I also see you are a chess.com premium member, so maybe you can use the Opening Explorer to investigate further (if you have a platinum or diamond membership), or you could use the many lessons (if you have diamond membership) to search up this opening and see what shows up.

There's also YouTube and surprisingly even Wikipedia has a good entry for some mainline chess openings. They may not be able to answer nuances, but they may at least point you in the right direction.

Yes, that's right, I'm referring to the Bg5 Najdorf. I used to play 6. ...e6, stopped playing the Sicilian altogether and now starting again. I'm just wondering if ...Nbd7 is better for the surprise value; it also seems to lead to more closed strategic positions, but my friend said the lines with ...g5 in 6. ...Nbd7 are super theory heavy...

Thanks for the advice, that's super useful. I'll have a look on chess.com, YouTube and Wikipedia. I always prefer Chessable for this kind of thing just because their courses are high quality, but Giri's course doesn't cover 6. ...Nbd7!

Oh okay, makes sense. A friend of mine has Giri's course for the Sicilian. I should play the 6...Nbd7 since they won't know it. xD

The main virtue of 6...Nbd7 is avoiding the high maintenance and largely irrational lines of the Poisoned Pawn.

Still I think that I prefer 6...e6, as Black need not enter the Poisoned Pawn. The following line is also very theoretical (the position after 32.Rf2 has been played no less than twelve times!), but at least it is rational, the moves of both sides follow some concrete plan and the position does not look like the pieces have been dropped on the board randomly.

The game is "flawless", which translates to "boring". Pretty much like any other "flawless" game that has been played in official correspondence chess the last 6-7 years.