What should I do to travel to Japan?

Open international roaming, but it's expensive. You may lose your phone bill with one phone call, and you may owe money.

Actually, you don't have to, but you can download a universal wireless network key in China and contact friends or relatives in China directly with WeChat after you arrive in Japan, because that's what I did.

Objectively speaking, in fact, most Japanese people are very friendly to China people. When I was in Japan, I met an elderly Japanese. The thing is, I was cutting my nails in the hotel lobby, and then a younger Japanese looked at me and cried. Then a China man who works in a hotel came up and said that I couldn't cut my nails in Japanese public places. In fact, the reason is not unsanitary, but that Japanese people are very taboo to cut their nails in public. There are many reasons, some of which are forced to say why Japan wanted to recruit at that time. When these people leave, they will cut off some nails and hair for their loved ones, so it means a little "pretending to be gone forever". Later, after that person's translation, I also talked with that Japanese for more than half an hour. He cried as he talked, saying that his father didn't want to leave before, but there was nothing he could do. If he doesn't go, he will be shot by the authorities. In fact, there were many such situations in Japan at that time. What I said is only a small part. Moreover, after listening to the old man's story, I hate the Japanese authorities even more. If Japan hadn't started the war, China and Japan might be very friendly countries today. Later, I went to a Chinese school in Japan, almost all of them were from China, but it was strange that all the teachers were Japanese. Later, after studying, these teachers really understood the Japanese crimes committed in World War II, so they taught in schools in China. According to them, it is atonement or something, but such a voice is almost unheard of in Japan.