The boost won't be that big. Japan still isn't the leader in trading. Also, somebody should investigate how their Bitcoin businesses are really doing.
I suspect there could be big interest in the currency but only out of curiosity and very little real use.
I heard rumours some Chinese whale traders switched to using Japanese exchanges after the Chinese government froze withdrawals on the Chinese exchanges. If that's true the end of the 8% consumption tax could be very bullish.
As I understand the Chinese exchanges have already resumed withdrawals on May 31, so those rumors might only be that, just rumors.
From what I read they are only allowing small withdrawals that are no use to whale traders. I think it might be 10 Bitcoins a day with a maximum of whatever a million dollars a year is in yuan.
I suspect there may be a great enthusiasts in currencies so that they know that the real user will very little, but I've heard that Japanese buying and using bitcoin as trade exchange rate very high value there other than reasonable so that if the Japanese Government ended 8% consumption tax on bitcoin because the increase that occurred in user bitcoin in Japan