Empress Masako is a Harvard- and Oxford-educated former career diplomat who married into Japan's imperial family more than 25 years ago, and became known for her struggles to adapt to one of the world's oldest royal families.

The 55-year-old, the second commoner after former Empress Michiko, 84, to wed the first in line to the throne, withdrew from all official duties after developing a stress-related illness some 15 years ago, but has been gradually expanding the scope of her activities in recent years.

(June 2011)

These have included visiting children at welfare facilities and learning about animal therapies for sick children.

"I want to devote myself to the happiness of the people, so I will make efforts to that end while gaining more experience," she said on the occasion of her birthday last December.

Born Masako Owada in Tokyo on Dec. 9, 1963, as the eldest daughter of then-diplomat Hisashi Owada, 86, a former vice foreign minister and judge at the International Court of Justice in The Hague, she spent her early childhood in Moscow and New York.

(6-year-old Masako at her home in New York, 1970)
[Supplied photo]

After returning to Japan, she joined Denenchofu Futaba Elementary School in Tokyo and studied at its junior and senior high schools before leaving for the United States again in 1979 after her father was posted to the Japanese Embassy in Washington and invited to Harvard University as a visiting professor of international law.

She majored in international economics at Harvard, graduating in 1985. She then joined the University of Tokyo's Faculty of Law to study politics before passing the Japanese Foreign Ministry's entrance exam in 1986.

(Graduation ceremony at Harvard, June 1985)
[Photo courtesy of the Imperial Household Agency]

During her time at the ministry, she worked in a section dealing with the Organization for Economic Cooperation and Development and was posted to Britain in 1988 as a probationary diplomat at the Japanese Embassy in London and studied at the University of Oxford's Balliol College for two years.

Fluent in English, French and German, she engaged in negotiations to resolve Japan-U.S. trade disputes after returning to Japan. The empress has twin younger sisters and is known to be good at softball, skiing and tennis.

She first met Emperor Naruhito in October 1986 at a party to welcome visiting Spanish Princess Elena. But after meeting several more times over the next year, they did not encounter each other again until August 1992.

The couple agreed in December the same year to marry, and the empress left the ministry after her engagement became official in January 1993. The two wed the following June in a Shinto ceremony at the Imperial Palace and during the procession in central Tokyo they were greeted by around 190,000 well-wishers on the streets.

She gave birth to Princess Aiko in 2001 after suffering a miscarriage in late 1999.

The empress began receiving treatment for a physical and mental ailment in late 2003.

The then-crown prince said in May 2004 of his wife that there were "developments that were regarded as denying Masako's career (as a diplomat) as well as her personality." Two months later, the Imperial Household Agency said she was diagnosed as having an adjustment disorder.

The disorder was widely believed to have been caused by heavy pressure to produce a male heir and adjust to life in the imperial family.

Japan's Imperial House Law limits imperial succession to male offspring in the male line. There has been debate over whether to allow female imperial family members to succeed to the throne but no substantial progress has been made.

(March 2002)

(With Dutch Crown Prince Willem-Alexander and his family in Apeldoorn, the Netherlands)
(August 2006)

"The situation in which I could not visit other countries for six years required a great effort for myself to adjust," the empress said at a press conference in 2002.

"She must well understand other people's pain as she has suffered herself from an adjustment disorder," said a person familiar with her recent activities of interacting with sick children.

Princess Aiko, now 17 and a third-year student at Gakushuin Girls' Senior High School in Tokyo, joined a summer school program at Eton College on the outskirts of London for more than two weeks last year after taking an interest in learning about other countries as her parents have.

She stayed in a dorm with classmates and studied English language and British culture.

The only child of the imperial couple had attracted wide public attention when she was temporarily absent from her primary school at the end of second grade after reportedly being shocked by the "rough behavior" of some boys and again when she became absent from junior high school for over a month due to fatigue.

But the princess has since recovered and has been seen enjoying school life, taking part in a basketball competition, dance performances and playing cello for a school play. She has also accompanied her parents on official duties as well as private skiing trips and mountain climbing.

At their Akasaka Estate residence, the family keeps a dog named "Yuri" and two cats "Mii" and "Seven."