Government of Japan
The Current Emperor of Japan (今上天皇) is Akihito. He was officially enthroned on November 12, 1990. He is styled as "His Imperial Majesty" (天皇陛下), and his reign bears the era name of Heisei (平成). Naruhito, the Crown Prince of Japan, is the heir apparent to the Chrysanthemum Throne.
Emperor Kōkaku
In 1817, Kōkaku abdicated in favor of his son, Emperor Ninkō. In the two centuries before Kōkaku's reign most emperors died young or were forced to abdicate. Kōkaku was the first Japanese monarch to remain on the throne past the age of 40 since the abdication of Emperor Ōgimachi in 1586. He was also the last Emperor to rule as a Jōkō (上皇), an emperor who abdicated in favor of a successor (it has been announced that the current Emperor, Akihito, has plans to abdicate in 2019, however, and would thus be the first Jōkō since then). Kōkaku travelled in procession to Sento Imperial Palace, a palace of an abdicated emperor. The Sento Palace at that time was called Sakura Machi Palace. It had been built by the Tokugawa shogunate for former-Emperor Go-Mizunoo.