All in all I am not really a fan of the Japanese kitchen. Nevertheless I went to Mifune from time to time only to enjoy their buffet. After several visits I observe there was never any changes what the buffet was offering. Moreover if you came somehow late and some things ran out, it was no longer filled up. So finally I also decided not to come back.
Years ago, so have no idea about the current situation, there was weekly also a Japanese buffet in Bambulo. But living on the north side of Dumaguete not within my distance to go there in the evening. A new Japanese restaurant @Northpoint (the extended boulevard) might be worth a try.