While the months and days are the same as the calendar used in most Western nations, the year is referred to in two ways. In commercial transactions and legal matters, for purposes of convenience, the Western date is generally used (there are frequent exceptions in documents written in Japanese, however). For almost all matters referring to uniquely Japanese events, however, the Reign Name is used. The first year that a new emperor (or empress) assumes the throne becomes Year 1 of that reign. 1989, therefore, was Heisei 1 (there was no Heisei 0, and Heisei 1 is identical to Showa 64 because of the overlapping Western dates). The year 2300 is therefore Uan 39.

The chart below shows the personal names and reigns of Japanese rulers since the close of the 20th century.

The current reign name of Uan means "peaceful universe," but the Kafer unfortunately made it impossible to achieve this dream.