Historically, why did China have to cede 10% of its territory to Russia???

#Historically, why did #China have to cede 10% of its #territory to #Russia???
Hello friends! In a recent speech by China's Foreign Minister Wang Yi, there was a saying that caught the attention of the international media. that is "Russia and China are not allies, but better allies". What is the true? Is the relationship between them close as stated by the Minister surnamed Wang? Let's find out together.