Now that Episode 49 has aired, let’s clear up the Zanpakuto lore once and for all: Ichigo never had a "fake" Shikai or Bankai, it was simply incomplete. Per Kubo’s Klub Outside Q&A 357, every true Zanpakuto consists of a blade and a scabbard, with only two exceptions born into the world without one: Oetsu Nimaiya’s Sayafushi (whose edge was too sharp for any sheath) and Ichigo’s original Zangetsu. It wasn't until Oetsu reforged Zangetsu at the Phoenix Palace that it took its correct, dual-blade form, the large Hollow blade serving as the scabbard and the small Quincy blade as the core blade When releasing Bankai, the two fuse into a single weapon where the outer white shell acts as the scabbard around the inner black sword; so when Yhwach shattered that outer layer, he merely stripped the scabbard to reveal the core blade underneath (explaining why it resembles his original Shikai), and by absorbing that broken scabbard back into his spiritual body, Ichigo can now freely switch between wielding the dual blades or the single blade