In a written statement issued for her 50th birthday Monday, Crown Princess Masako pledged to continue efforts to overcome a stress-induced illness that she has been dealing with for 10 years.

"I have tried to complete my public and private duties as much as possible this year, and I will continue efforts to make a full recovery," she said through the Imperial Household Agency, referring to her health issues.

The Crown Princess visited the Netherlands this spring to attend the coronation of Dutch King Willem-Alexander, her first official overseas trip in 11 years.

A team of the Imperial family's doctors described the trip as a great opportunity to boost her confidence.

"Her recovery continues slowly but surely," the team said in a statement. "Her health is still on its way to recovery. Too much expectation may cause an adverse effect."

The Crown Princess also visited Fukushima, Iwate and Miyagi prefectures this year, for the second time since the three prefectures were hit hard by the March 2011 earthquake and tsunami.

"I would like to continue focusing my attention on reconstruction efforts for a long time," she said while expressing sympathy for those whose lives have been affected by the disaster.

As for her 50th birthday, she said, "It feels strange to think I have already lived for half a century."

She also expressed her gratitude for the continuous support of her husband, Crown Prince Naruhito, as the couple celebrated their 20th wedding anniversary in June.