Emperor Naruhito and Empress Masako celebrated their 30th wedding anniversary on Friday, saying in a statement they felt "deeply emotional" as they reflected on the decades spent together and thanking the public for their support.

"We are deeply grateful for having been able to experience many things together and come this far by helping each other and sharing joys and sorrows while receiving support from many people," the couple said.

Their married life has seen the birth of their only daughter, Princess Aiko, now 21, and the 63-year-old emperor's May 2019 enthronement, launching a new imperial era. But it has also seen the 59-year-old empress struggle with long-term mental health issues.