Gōkei

is a technique of Byakuya Kuchiki's Bankai, Senbonzakura Kageyoshi.

Description
This form increases the number of tiny blades immensely. It creates a spherical formation of innumerable blade fragments, which swirl around the opponent like a cloud. It then flies into them from every possible angle, leaving no blind spots and no possibility of escape. It then collapses on itself, destroying the opponent. It was strong enough to completely obliterate a very large building from the inside out, and the resulting shock-wave generated by the attack is so powerful that Byakuya himself has to use Shunpo to get away.