Why is it so difficult for China to immigrate to Japan?

By the end of this century, Japan will sink into a part of the ocean, including Tokyo. After Tokyo sank to the bottom of the sea, it moved its capital to Okayama Prefecture. Japan is a country with many earthquakes, and its citizens have a strong sense of hardship, which is also the main reason why the Japanese like to invade other countries. In addition to sinking, the Japanese are now facing a greater disaster, that is, nuclear leakage, Fukushima wastewater has not been completely treated!