Imperial Japan refers to the period of Japanese history between 1868 and 1947 when the country was ruled by an emperor. However, there are several synonyms to the term Imperial Japan, including the Meiji period, Taisho period, and Showa period. Each period represents a specific era in the Japanese imperial history defined by significant events such as the Meiji Restoration, the World War I, and the bombing of Hiroshima and Nagasaki during World War II. While Imperial Japan is a commonly used term, it's important to acknowledge and use the appropriate synonyms depending on the specific period being referred to in Japanese history.