Within the Nihon Shoki, Yomi appears as the shadowed realm of the dead, a place marked by impurity, decay, and separation from the living. Its significance is revealed most clearly in the myth of Izanagi and Izanami, where Izanami, having died in childbirth, descends to this underworld. Izanagi’s journey after her traces the boundary between life and death, as he seeks to reverse what has already become cosmically fixed. The revelation of Izanami’s decomposed form, swarming with corruption, makes Yomi not merely a distant locale but a symbol of the defilement bound up with death itself. This encounter underscores that death is not a neutral transition but a state that stains and disturbs the order of the living world.

The flight from Yomi and the sealing of its entrance with a great boulder dramatize the permanent rift between the realms. The slope of Yomi and the blocked passage articulate a cosmos in which the world of the living and the land of the dead are decisively sundered, so that the dead do not return. Izanami’s wrathful vow to kill a thousand people each day, and Izanagi’s counter-vow to bring forth one thousand five hundred births, transforms this separation into a mythic explanation for the ongoing rhythm of mortality and renewal. Yomi thus functions as a dark counterpoint to the living world, a necessary pole in a cycle where life continually arises in the face of inevitable death.

Equally important is the way Yomi gives rise to the need for ritual purification. Izanagi’s contact with the underworld leaves him polluted, and his subsequent ablutions become the paradigmatic act of cleansing away the taint of death. From this misogi emerge major deities such as Amaterasu, Tsukuyomi, and Susanoo, suggesting that even from the encounter with corruption and loss, new divine order can arise. In this way, Yomi is not simply a place of negation; it is the dark background against which the value of purity, the structure of the cosmos, and the continuity of life and divine presence are thrown into sharp relief.