Mitama is the honorific term for a spirit or soul in Shinto, the spirit of a kami, and also of a human being, particularly of the dead. The word joins an honorific prefix to tama, spirit or soul, and it is used in the naming of enshrined spirits and in ritual address.
The doctrine most often associated with it is the ichirei shikon, "one spirit, four aspects": the analysis of a single spirit into four functional aspects. Aramitama is the rough or violent aspect, associated with force, courage, and the power that advances and destroys. Nigimitama is the gentle or harmonious aspect, associated with peace, order and blessing. To these are added sakimitama, which grants blessings and prosperity, and kushimitama, the mysterious or wondrous aspect associated with wisdom and transformation. The first pair is older and better attested in the early sources; the fourfold scheme is systematised later, particularly in Edo-period and modern Shinto theology, and scholars are careful to distinguish these strata rather than presenting the whole as ancient.
The distinction has practical ritual consequences. A kami's rough and gentle aspects may be enshrined separately, and there are shrines that do so, the arrangement at Ise, where the Aramatsuri-no-miya enshrines the rough aspect of Amaterasu, is the standard example. Underlying this is a general Shinto approach to the sacred as ambivalent power. A kami is not simply benevolent; ritual serves both to invoke blessing and to pacify what might otherwise be destructive, and the same power that protects can harm if not properly attended to.
The logic extends to the historically important practice of goryo: the enshrinement and appeasement of the spirits of people who died with grievance, so that their anger is converted into protective power rather than left to work as affliction. The most cited case is Sugawara no Michizane, a scholar-official who died in exile in 903 and whose death was followed by a series of disasters at the capital read as his doing; he was enshrined, and became Tenjin, one of the most widely venerated kami in Japan and the patron of learning to whom students still pray before examinations.