Emperor Naruhito and Empress Masako attended a national tree-planting ceremony in Shimane Prefecture online on Sunday, their first virtual presence at a major event outside Tokyo amid the coronavirus pandemic.

The couple took part in the event, which was postponed by one year, from the Akasaka Imperial Residence in Tokyo, observing the ceremony through a large screen.

Emperor Naruhito and Empress Masako attend a national tree-planting ceremony online from Akasaka Imperial Residence in Tokyo on May 30, 2021. (Pool photo)(Kyodo)

"I hope that the 'green cycle' of planting, growing, using, and planting again will be widely practiced," Emperor Naruhito said via livestream.

The imperial couple then each planted two types of seeds chosen from Shimane Prefecture, including a cedar tree and a mountain cherry tree, in boxes. They will be sent back to the prefecture at a later date for replanting.

The National Arbor Festival is one of the four annual events the emperor has traditionally attended in Japan, along with the National Sports Festival, the National Culture Festival and the Festival for the Cherished Sea.

All were postponed last year due to the coronavirus pandemic, with Sunday's festival marking the first time any have been held virtually.