Blessed Crest of Yatagarasu

The Blessed Crest of Yatagarasu is a seal unique to Yūmei Kokūzō, and is located on his chest over where his heart is supposedly located. The seal consists of four tomoe, two on each side of a Yin-Yang symbol with a bird positioned above them with one wing outstretched which when activated causes six tomoe to gradually expand from the seal in a circular-formation. Like the Cursed Seal of Heaven, the user receives increased chakra levels and physical capabilities (strength, dexterity, constitution e.t.c.) when the seal is active, although it is also like the Yin Seal, capable of building up and storing the user's chakra inside of the seal only to self-activate whenever they're under the effect of low to medium tier genjutsu.

Trivia
Although Yatagarasu is mentioned in a number of places in the Shintō canon, there is very little explanation, and much of the material is contradictory. This great crow was sent from heaven as a guide for Emperor Jimmu on his initial journey from the region which would become Kumano to what would become Yamato. It is generally accepted that Yatagarasu is an incarnation of Taketsunimi no mikoto, but none of the early surviving documentary records are quite so specific.
 * This seal is a modification of Shinobi Legend's Seven Star Tattoo Enhanced.
 * In Japanese mythology, this flying creature is a raven or a Jungle Crow called Yatagarasu (八咫烏?, "eight-span crow"); and the appearance of the great bird is construed as evidence of the will of Heaven or divine intervention in human affairs.