The Japanese word mitama (御魂・御霊・神霊 honorable spirit?) refers to the spirit of a kami or the soul of a dead person. British Japanologist William George Aston (1841-1911) believed the mitama to be comparable as a concept to the Jewish Shekhinah.
Early Japanese definitions of the mitama, developed later by many thinkers like Motoori Norinaga, maintain it consists of several "souls", relatively independent one from the other. The most developed is the ichirei shikon (一霊四魂?), a Shinto theory according to which the spirit (霊魂 reikon?) of both kami and human beings consists of one spirit and four souls. The four souls are the ara-mitama (荒御霊・荒御魂 rude soul?), the nigi-mitama (和御霊・和御魂 harmonious soul?), the saki-mitama (幸御魂 happy soul?) and the kushi-mitama (奇御霊・奇御魂 wondrous soul?). According to the theory, each of the souls making up the spirit has a character and a function of its own; they all exist at the same time, complementing each other. In the Nihon Shoki, kami Ōnamuchi actually meets his kushi-mitama and shiki-mitama, but does not even recognize them. The four seem moreover to have a different importance, and different thinkers have described their interaction differently.