Shūkei: Hakuteiken

is a bankai technique used by Byakuya Kuchiki's Zanpakutō, Senbonzakura Kageyoshi.

Description
This condenses each and every single one of his blades into a single, potent sword, drastically increasing its cutting power. The spiritual energy and pressure of this form released is immense. The blade appears bright white and its aura takes the form of a bird, earning it the name. Pure white wings form on Byakuya's back, as well as a halo-like circle, made of concentrated spiritual energy. The blade in this form is dangerous enough to cause aggravated injuries in one single blow. The wings are capable of being used for flight. Whether or not this form allows only one single attack or more is as yet unknown.