looking to learn how to surf here in Japan? Check out
SplashGuestHouse they do great surf lessons in Chiba and are really easy to get to only 1.5hrs by bus from Tokyo station or on the train. They also have a great learn how to surf video which you watch before the lesson.
they have a sister site called
Surfing In Japan as well .
If you are just looking to rent a surfboard they do all that as well , many many happy customers. Well recommended.