Emperor Akihito of Japan underwent successful heart bypass surgery and was in stable condition, with doctors saying he could leave the hospital within two weeks.
The New York Times quoted Dr. Ichiro Kanazawa of the the University of Tokyo Hospital as saying that while it was unclear when the 78-year-old would be able to resume his official duties, he expected the emperor to once again be able to enjoy his favorite sport of tennis.
Akihito’s son, Crown Prince Naruhito, stepped in for him after the procedure, which according to the Associated Press involved repairing two of the three coronary arteries using a blood vessel from another part of his body.
Minoru Ono, one of the doctors who helped perform the four-hour operation, told reporters that: "As far as operations go, it probably could not have proceeded any better."
An emperor's duties are largely symbolic. However, according to Reuters Akihito — who ascended to the throne after the death of his father, Hirohito, in 1989 — has spent the past two decades working to bring the monarchy closer to ordinary Japanese.
Akihito had surgery for prostate cancer in 2003 and suffered stress-related health issues in late 2008, Reuters reported.
In 2009, the Imperial Household Agency said he would cut back on official duties. However, last year's devastating earthquake and tsunami, and the resulting nuclear crisis, have reinforced the monarchy's importance as a source of comfort in Japan's traditionalist society.
Akihito in April traveled to the disaster area with Empress Michiko.