Crown Prince Akishino and Crown Princess Kiko quietly marked 30 years of marriage on Monday as the novel coronavirus pandemic continued to restrict their public appearances.

The 54-year-old crown prince was initially scheduled to take part in a ceremony April 19 to proclaim his new status as first in line to the chrysanthemum throne, but the event, a key part of imperial succession ceremonies, was postponed to prevent the spread of coronavirus infections.

The crown prince and his 53-year-old wife have been receiving online lectures on the coronavirus and last month donated 500 medical gowns they made by hand out of plastic bags with their children and Imperial Household Agency officials for use by health care workers.