His Imperial Highness Crown Prince Naruhito of Japan called for a reduction in His Imperial Majesty Emperor Akihito’s official duties following heart bypass surgery last week, as the first in line to the throne marked his 52nd birthday Thursday.

“Considering the Emperor’s age, it is necessary to cut down on his burden,” the eldest son of the 78-year-old Emperor said at a press conference given prior to his birthday.

“I would be more than happy to do anything if I can be of help to him,” the Crown Prince said.

The Crown Prince also said the Emperor had been complaining of slight heart discomfort for some time prior to the surgery, which was conducted Saturday after an angiogram showed a narrowing of two of his three coronary arteries.

On the introduction of an age limit for Japan’s Emperor, who currently remains on the throne for the rest of his life, the Crown Prince declined to comment specifically, only saying, “I think there are various options available” regarding how to reduce the Emperor’s burden.

The Crown Prince also refrained from clarifying his stance on whether female members of the imperial family should be allowed to create their own family branches so they can retain their imperial status after marriage.

Amid concern that the number of imperial family members will continue to decline given the large number of female members and fewer male members, the government is set to hold the first hearing on the matter later this month.

On the upcoming first anniversary of the March 11, 2011, earthquake and tsunami disaster, the crown prince said the catastrophe has constantly been on his mind during the past year.

“I feel truly encouraged by the fact that people affected by the disaster are making efforts hand in hand toward reconstruction despite harsh conditions,” he said.

Referring to Her Imperial Highness Crown Princess Masako, whose official duties have continued to be limited as she has been receiving treatment for stress-induced illness, he expressed hope that she will “gradually expand the range of her activities” while making her recovery “the top priority.”

Regarding their only child Her Royal Highness Princess Aiko, the Crown Prince said his daughter now feels secure at school by taking part in a brass band and field trips. She is now attending school without being accompanied by her mother.

On Thursday morning, the Crown Prince visited University of Tokyo Hospital to greet the emperor who is now recuperating from the surgery and undergoing rehabilitation.