who was the best Russia chess player in the history

Kasparov.

kramnik and kasparov both come to mind. after them, karpov, then spassky, korchnoi, tal, smyslov, if we were to consider only world champs, in my opinion. 

”kramnik and kasparov both come to mind. after them, karpov”

Depending on the definition of ”best”, I’d have Karpov ahead of Kramnik if it was about greatness. The latter at best shared first on two rating lists while Karpov was clear #1 a whole decade. My top three would be Kasparov, Karpov and Botvinnik. If it was about playing strength maybe Nepomniachtchi and Grischuk would belong with Kasparov in the top three.

soviet chess players

It's impossible to know who was the best in history but it could be  Andor Lilienthal and Boris Spassky, ex equo with Tom Jones

https://www.chess.com/blog/Spektrowski/boris-spassky-2016-interview

Kasparov if an Azerbaijan born player counts and if not I must think about it.

Leonid stein was certainly amongst the strongest

M. Chigorin

1. Kasparov
2. Botvinnik
3. Alekhine
4. Karpov
5. Kramnik
6. Korchnoi

Kasparov was not Russian, he was Soviet & Azerbaijani.

Fair. By those rules then I suppose Karjakin would not count either.

I think given that he chose Russia in 2009 and played for the Russian rather than Ukranian Olympic team, that he could count either way.

@12

"Yes, I am born in Baku and I am half Armenian-half Jewish, but my native
tongue is Russian, my culture is Russian, my education is Russian' - Kasparov