TOKYO (Kyodo) -- Japan's Empress Masako, on the occasion of her 61st birthday Monday, reflected on a year that included a "memorable" state visit to Britain with Emperor Naruhito and a tour of their shared alma mater, Oxford University.

"To be able to re-visit the nostalgic Oxford University after 34 years was a special opportunity, and I was deeply moved," the empress said in a statement released by the Imperial Household Agency. She thanked Japanese and British officials for arranging the June visit.

Looking back on the year's events, she said the Nobel Peace Prize win for the Japanese atomic bomb survivors' group Nihon Hidankyo had left an impression on her.

Referencing their efforts to abolish nuclear arms, the empress said she "felt anew the importance of the people of the world striving for mutual understanding and working together to build a peaceful world."

She also mentioned Los Angeles Dodgers baseball player Shohei Ohtani, who won a third MVP award this year, as an example of athletes whose unfailing dedication "offers hope and courage to many Japanese people."

A former diplomat who also attended Harvard University, the empress has been struggling with adjustment disorder since 2003.

In a separate statement, her doctors said her treatment is ongoing. While noting the empress made numerous public appearances this year, they said she requires time to recover after significant engagements or busy periods.

Turning to family, the empress remarked that the couple's 23-year-old daughter, Princess Aiko, began work at the Japanese Red Cross Society from April while she also took on official duties, including her first solo regional visit to the Japan Games in Saga Prefecture.

"I hope Aiko can accumulate a variety of experiences as a member of society while taking care of her health and fulfill her duties as a member of the imperial family," she said.