I played 7. Rc8 for a reason. Now taking on c5 is forced, on any other move, say castles:
7. Bd3 Rc8 8. O-O cxd4 9. cxd4 Nb4!
Now white's ls bishop cannot be spared because 10. Be2 now runs into 10. ... Nc2! which wins the rook.
Also there was a reason I played 10. ... Be7, because otherwise white has 11. b4 which kicks the bishop, then 12. b5 which kicks the knight. This is not that frigthening according to the engine, but may be inconvenient in a human to human game. May be 10. ... a6 would have been better to meet this.
white can play 8 a3 but yeah, Rc8 is definitely better than i thought. black isn't losing anything.
10..Be7 though.. it's still bad. i felt you might have wanted to do profilaxis against b4-b5, but it's really no big deal. Bb6 is not bad at all, and on b5 Na5! then c3 will be very weak and it's very awkward to prevent Nc4 (like Nd2 allows Nf4).
if you don't want to go into it, your a6 suggestion is definitely still much better than Be7.
i thought a5 is a more common idea in this structure, but a6 is probably just better in that specific position. you are very well prepared to meet b4 and white hasn't played a3, so there's no reason to give away a hole on b5 (mainly worried about Na3-Nb5, which isn't possible if a3 was played).
@sakkozik I don't really understand what you're trying to do with 13... Na7. It makes sense that you want to move the knight to b5, but I don't get why you just moved it back to c6, a7, c6, etc.
Also, after 22.Re1 , I think you should have gone with 22.Qa5 , and I dont think white has a way to protect his a-pawn or to kick your knight. I think you could have done more with this position.
13. ... Na7 is aimed at playing 14. ... Bb5 to trade bishops. While the engine does not like this trade at all, still my opponent percieved as a threat and acted, first with attacking the knight with 14. Be3, which leaves the e5 pawn undefended, and when I moved back the knight 14. ... Na7 to point this out, then 15. Bd2 was played. I renewed the threat with 15. ... Na7 and white finally acted on it with 16. a4, which created a weakness that I could use to finally force the draw.
We are not engines and among humans trading the ls bishop was perceived as a threat, so my calculation that my opponent will act on it proved to be correct.
8. a3 is not good because then I can play 8. ... c4. Once there is no pawn on a2 to support b3, this move becomes legitimate. There is a whole theory what to do when a3 is played in this setup, black will play Na5, Qb6 to further block b3. White probably wanted none of this and took on c5 instread.