While the Japanese use our calendar for practical purposes, they officially start a new era every time an emperor takes office. This is, for example, Heisei 29 in Japan, not 2017. We do a version of the same thing. We talk of the “Clinton years,” or the “Bush years,” and even link cultural events to the reigns of our presidents, none of which last more than eight years. We talk about Reagan-era fashions, for example.