A Diplomat in Japan, subtitled "The inner history of the critical years in the evolution of Japan when the ports were opened and the monarchy restored, recorded by a diplomatist who took an active part in the events of the time, with an account of his personal experiences during that period" is a book by Ernest Mason Satow, British scholar, diplomat and Japanologist, based mainly on his diaries. The book describes the years 1862-1869 when Japan was changing from rule by the Tokugawa shogunate to the restoration of Imperial rule.