I would recommend using a bus only if you want to leave Tokyo, since train’s and taxi are generally better suited for the city. Unlike Japanese taxi’s drivers which you can show a map of the location you want to go, and Japanese train’s which have become easy to use in recent years because of more frequent use of English, buses have remained the same.
Using a bus in Japan will require some basic proficiency in the language as all bus stops are in Japanese and the bus driver lack the time and ability to help you.