I want to learn Japanese. I can't speak a word when traveling in Japan.

It is no problem to travel to Japan without Japanese. First of all, Japanese characters are everywhere, and the goods in stations and shops are written in Chinese characters that China people can understand. In addition, there are Chinese service personnel in general stores. Chinese is also spoken on the radio. So traveling to Japan is more convenient than going to any other country. Teaching you a few words of Japanese now is just a simple greeting, which won't have any effect in Japan. And if your pronunciation is not good, the Japanese will understand.