Japan's 78-year-old Emperor Akihito underwent successful heart bypass surgery Saturday and should begin rehabilitation in a few days, doctors and palace officials said. Japanese Emperor Akihito and Empress Michiko arrive at the entrance of University of Tokyo Hospital in Tokyo Friday, Feb. 17, 2012. Akihito has entered the hospital for scheduled heart bypass surgery. Japanese Emperor Akihito, right, is greeted by doctors upon his arrival at the entrance of University of Tokyo Hospital in Tokyo Friday, Feb.