TOKYO >> Japanese Emperor Akihito checked into the hospital Friday for heart-bypass surgery that doctors say will allow him to lead a healthier, more active life.

The surgery scheduled for Saturday will last about five hours to repair two of three coronary arteries that had narrowed, using a blood vessel from another part of his body, as is routine with such operations, the Imperial Household Agency said.

A medical team from University of Tokyo Hospital, where the 78-year-old emperor is staying, will work with doctors from Juntendo University Hospital for the operation.

Akihito is expected to be released in about two or three weeks if there are no complications, the agency said.

Akihito got tests last weekend that showed his heart condition had worsened from a year ago.

The gently spoken Akihito holds no political powers but is extremely popular with Japanese people as a symbol of the nation. He is often seen playing tennis, enjoying music and taking walks with his wife Michiko.

A special notebook has been set up at the palace for get-well messages, but the emperor does not accept gifts or flowers, according to the agency.

Akihito performed his regular duties Thursday, including meeting with four Japanese ambassadors and elementary school officials. Crown Prince Naruhito, Akihito’s son, will perform such duties during the hospitalization.