User blog comment:Xilinoc/Ch. 551 - The Burnt Offerings/@comment-11446176-20131004064733/@comment-5398287-20131004220018

While Isshin's Zanpakuto is more energy with the appearance of fire, Bazz-B appears to be strong enough for Isshin to use his Bankai against, provided that Urahara tells him how to prevent Bazz-B from taking it/get it back once stolen.