Heikoki is a diary of Shonii (Senior Second Rank) Minbukyo (Minister of Popular Affairs) TAIRA no Tsunetaka. It is also called "Tsunetaka Kyoki" (Diary of Lord Tsunetaka). The extant manuscript covers 50 years from 1196 to 1246. It is a basic historical document which gives an understanding of the Court Council and political situation in Kyoto in the early Kamakura Period. The title "Heiko" (平戸) came from the surname Taira (平) and "Kobushosho" (戸部尚書), the Chinese name of Minbukyo.