Emperor Akihito is preparing to step down from the throne, becoming the first Japanese monarch to abdicate in more than 200 years, the BBC reports.
Tuesday's ceremonies began with private rituals in Tokyo's Imperial Palace.
The 85-year-old has been given legal permission to abdicate after saying he felt unable to fulfill his role because of his age and declining health.
His son, Crown Prince Naruhito, will ascend the Chrysanthemum throne the next day, beginning a new era.
The emperor in Japan holds no political power but serves as a national symbol.
Emperor Akihito's reign has been marked by his interactions with people suffering from disease and disaster, which have endeared him to many Japanese people.