Thread:Silver-Haired Seireitou/@comment-25456115-20150108080909/@comment-2089817-20150109060846

Reiatsu is one outlet of using reiryoku, for Shinigami, hence why Aizen said a battle between Shinigami is a battle between spiritual pressures. For example, Quincy express their reiryoku as "Spirit Weapons", by using their reiryoku to pull together reishi into a shape. There are many ways to express one's spiritual power, but reiryoku is the foundation and base of them all. An energy reserve ripe for use.