Prince Hisahito spends time with his father, Crown Prince Fumihito, looking over books in Akasaka Estate on Aug. 5. Hisahito celebrated his 15th birthday on Sept. 6. (Provided by the Imperial Household Agency)

Prince Hisahito, the second in line to the throne, marked his 15th birthday on Sept. 6 following a summer of taking field trips and studying. 

Hisahito, the son of Crown Prince Fumihito and Crown Princess Kiko, is a third-year student at Ochanomizu University Junior High School in Tokyo.

Although his activities were restricted this past summer amid the COVID-19 pandemic, he actively participated in events inside and outside his school while remaining healthy, according to the Imperial Household Agency.

The agency said that Hisahito went on field trips for three consecutive days in June because his school trip was canceled due to the pandemic as COVID-19 cases surged across the nation.

Hisahito listened to the story of a disabled worker at a flower shop. He also rode on a water bus and saw Olympic-related facilities and other sites from Tokyo Bay.

He spent a lot of time studying during the summer break in preparation for entering high school next year, according to the agency.

Last fall, he received an honorable mention in the junior high school student section of a children’s nonfiction literature awards for his work, “Visiting the Ogasawara islands.”

In his essay, Hisahito wrote about the islands he traveled to with his mother in 2017 and the friendly exchanges they had with islanders.

In March, the awards ceremony was held in Kita-Kyushu, Fukuoka Prefecture, and Hisahito attended it online.

“I would like to cherish the encounters I had and the memories of visiting the Ogasawara islands,” he said.