Kujiki (旧事紀?), or Sendai Kuji Hongi (先代旧事本紀?), is a historical Japanese text. It was generally believed to have been one of the earliest Japanese histories until the middle of the Edo period, when scholars such as Tokugawa Mitsukuni successfully contended that it was an imitation based on the Nihon Shoki, the Kojiki and the Kogo Shūi. Scholarship on the Kujiki generally considers it to contain some genuine elements, specifically that Book 5 preserves traditions of the Mononobe and Owari clans, and that Book 10 preserves the earlier historical record the Kokuzō Hongi.
Ten volumes in length, it covers the history of ancient Japan through Empress Suiko, third daughter of Emperor Kinmei. The preface is supposedly written by Soga no Umako (+626). While it includes many quotes from Kojiki (712) and Nihon Shoki (720), volumes five and ten contain unique materials. The overall composition is considered as having been compiled between 807 and 936.
The Kujiki contains 10 volumes, but there are 3 false documents also called Kujiki, produced in the Edo period: the 30 volumes Shirakawa edition, Shirakawahon Kujiki (白河本旧事紀) (kept by the Shirakawa Hakuou family), the 72 volumes Enpō edition, Enpōhon Sendai Kuji Hongi Taiseikyō (延宝本先代旧事本紀大成経) (discovered in 1679), and the 31 volumes Sazaki succession edition, Sazaki Denhon Sendai Kuji Hongi Taiseikyō (鷦鷯伝本先代旧事本紀大成経).