Learn your own history potato head. Russian held outer Manchuria a 350,000 Km2 land mass(France 550,000) with Russia's most important port Vladivsstok located at the far eatern tip. Area is rich in minerals and petroleum products that China desperately need.
https://en.wikipedia.org/wiki/Outer_Manchuria
You can thank me later for educating you on your own geography.
