There is no version of a pentagram in Japanese culture. You're applying Western cultural thinking again, and it doesn't apply here.
In addition, as a pagan, can I say that I find the automatic association of a pentagram with evil highly offensive? Despite its adoption by certain Christian-inspired offshoots like Satanism, it is not an evil symbol at all. I don't mock the symbols of other faiths, and it would be nice, albeit rare, to receive the same courtesy.