Shūkei: Hakuteiken

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

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