Tokyo ? Japan’s Princess Aiko, granddaughter of the emperor, has missed several days of classes because of bullying by boys at her elementary school, a spokesman for the royal family said Friday.

The news provided a rare glimpse into the private affairs of the world’s oldest hereditary monarchy, which usually abides by strict, formal protocols and is tight-lipped about personal matters.

The 8-year-old princess complained of a stomachache and expressed deep anxiety and has not attended school since coming home early Tuesday, the spokesman for the Imperial Household Agency said. He declined to provide his name, citing agency policy.

An investigation by the agency and the school revealed that she and several other students had suffered “violent things” from boys in another class, the spokesman said, declining to elaborate.

The story is likely to shock Japanese. The imperial family is treated with deep reverence in the country, where Aiko’s great-grandfather, Emperor Hirohito, was worshiped as a living god until Tokyo’s defeat in World War II.