On: China has passed a national security law for Hong Kong

[baybal2]

Yes, they had an alliance in a manner of vassalage in exchange for khan's troops.

It was basically the khan saying them "I will back you if you submit a bigger chunk of Russian land to me"

It was like that with Mongols, and many other foreign invaders before, and after them. Both by Muscovy, and by duchies apposing it.