What exactly do you understand under "exist"? XD
Well, there are a LOT of (especially American) guys who are married to Japanese women and believe me when I say their Japanese is veeery basic.
You can live and survive here with no to basic Japanese, but it's no fun, I guess. It wouldn't be for me at least. I wanna understand the tv shows, magazines etc. and everyting else as well XD

Where exactly are you going in Japan? :)