The territory occupied by Russia, such as Sakhalin Island, is more than one million square kilometers! China government doesn't want it? I haven't seen anything written in history textbooks.

Yes, the government has given up. The government generally believes that this was ceded by the Qing dynasty and is not the responsibility of the current government. Moreover, Russia has never been a weak country, and China has neither the ability nor the courage to force the other side to do anything. So we delude ourselves into thinking that this is our own generosity. Of course, Russia never thought so. The courage and strength they admired, since their former Russian empire forced the Qing government to sign a treaty at that time, the treaty was legal and effective, and demarcation was only an recognition and compromise of this strength. Therefore, Russia will not feel any guilt or shame. Similarly, the land dispute between Russia and Japan is now the same. Since Russia is the actual owner of the disputed land, what is he afraid of? Japan dare not wage war with him, and any other measures are powerless in the face of the interests of land and resources. So, in order to recover those lands, I'm afraid you have to expect China people to emigrate to Primorsky Krai, far more than Russians, and then the government of the Russian Federation will be in civil strife like the disintegration of the Soviet Union, unable to control the local situation, and then this place will be independent and autonomous, and finally a referendum will be held to join People's Republic of China (PRC). . . . Of course, there is another way for you, that is, at the risk of all-out nuclear war, at the risk of more than half of the country's casualties, and at the risk of economic retrogression to the Stone Age, Russia makes military threats and then directly moves troops to occupy it. However, compared with this method, the above-mentioned dream of independent integration into China is more reliable. Although this possibility is now close to zero