You don't need to know Japanese to travel in Japan, but it sure does help a lot if you do know some Japanese (and it would be appreciated by Japanese people since some are scared of foreigners due to the language barrier). Unless you are a linguistic genius, it'll usually take people years to learn Japanese.
But what if you have an opportunity to go travel in Japan soon than later? How will you be able to learn Japanese in that limited amount of time? You can't, and that's why I'm here to tell you the survival Japanese you should remember. I did a post on the Japanese you should know if you're trying to learn but this article is going to be talking specifically about Japanese that will make or break you in Japan.