Crown Prince Akishino, who was formally declared as first in line to the chrysanthemum throne on Sunday, is known for publicly speaking his mind about the role of the imperial family in modern-day Japan.

The 54-year-old younger brother of Emperor Naruhito, 60, has occasionally expressed his view that the imperial family needs to adapt to the times while saying he will work alongside and support his brother, who ascended to the throne in May last year.

On the occasion of his 52nd birthday in 2017, he said, "Of course, I think what (people) seek from us changes depending on the times. I think we need to always keep that in my mind."