The abdication of Japan's Emperor Akihito next year will be quite literally the end of an era, the Heisei era of his rule, and behind closed doors, talks about the next era have begun. It might be 2018 in much of the world, but because Japan uses traditional imperial calendars, it is Heisei 30, or 30 years into Akihito's reign. While the Gregorian calendar is widely used in Japan, imperial dates feature on government documents, newspapers, and commercial calendars.