Minamotono Mitsuyuki comments on a verse in the “Rikyō-Hyakuei”, in the first chapter on the moon of his “Hyakuei-waka”. He says that ‘broken mirror’ is one of the names of the moon, and he adds a waka as a commentary. The stories he cites as evidence are the so-called “broken mirror” narratives. In these stories, ‘half mirror’, ‘half light’ and similar expressions are used as an equivalent of ‘broken mirror’.In other Japanese notes and commentaries, the ‘half mirror’ and the ‘broken mirror’ are regarded as synonyms, but that doesn’t seem reasonable: The usages of ‘broken mirror’ include the meaning of the ‘half mirror’ as the half of the full moon and the meaning of a cosmetic tool, while the usages of ‘half mirror’ cannot include those of ‘broken mirror’.The meaning of ‘broken mirror’ covers wider than that of ‘half mirror’. For example, one usage of ‘broken mirror’ in the Taiping yulan is explained by a commentator as the name of a beast.Moreover, ‘broken mirror’ can be used not only as a simile of the half moon, but also as the half of the month. On the other hand, the ‘half mirror’ can mean the half-moon as well as the cosmetic tool.This presentation intends to illustrate the meanings of ‘broken mirror’ and ‘half mirror’ through an investigation of Japanese and Chinese texts, considering the contexts, collecting the usages and taking cosmological connotation into account.