Princess Aiko arrived in Osaka on Thursday to visit the World Exposition, which is running in city.
This is the second independent official duty for the only child of Emperor Naruhito and Empress Masako outside Tokyo. In October last year, Aiko attended the Japan Games, a major national sports event, in Saga Prefecture.
The 23-year-old princess was scheduled to inspect the Grand Ring, the huge wooden structure that is a symbol of the expo, on Thursday afternoon.
She was also slated to visit the International Red Cross and Red Crescent Movement Pavilion run by the Japanese Red Cross Society, which she works for.
On Friday, the princess will inspect the Singapore Pavilion, Commons A Pavilion for Kenya and several other countries, and Earth Mart, a food-themed pavilion.
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