I'm not sure that a surge in Japanese consumers has actually resulted in that much of a surge in demand.  Maybe a little bit, but I think the balance of skepticism and optimism with a hard fork has been the main factor for a while and might continue to be.  I don't think that too many Japanese people are going to think, "Wow! I have to register my identity on exchanges now! I'd better buy some Bitcoin!  So, what's the best exchange nowadays?  Mt. Gox?"