Chusei Nihongi collectively refers to a set of Japanese mythologies that were variously reinterpreted and revised based mainly on the Honchi Suijaku theory (the theory that Japanese deities were the multi-faceted embodiment of Buddha) in the medieval period while founding its base on classics such as "Nihonshoki" (Chronicles of Japan).
中世日本紀（ちゅうせいにほんぎ）は、日本中世において、『日本書紀』等に基づきながらも主に本地垂迹説などに則り多様に解釈・再編成された神話群の総称である。