World home run king and Japan's top baseball manager Sadaharu Oh underwent an operation on his stomach after he was diagnosed to be suffering from the early stages of stomach cancer. The operation was conducted on Monday (July 17) at the Keio University Hospital in Tokyo. At a news conference on Tuesday (July 18), doctors told reporters the operation was successful. "The operation finished successfully. Mr. Oh returned to the patient room from an intensive care unit this morning before 9am. Then I heard that since then he had walked around the room for five times." said Masaki Kitajima, attending physician in charge of the surgery. A digestive surgery team led by Kitajima decided to remove all of Oh's stomach by using abdominoscope because they found a tumor in nearby lymph nodes. However, the doctor said they found no other tumors in other part of the body and concluded that the cancer was successfully removed in the early stage. " I think he can leave the hospital in around ten days though we have to discuss it with his family first." Kitajima said. Oh was hospitalized on July 5 after doctors found the five-centimeters(2 inches)-wide tumor in the stomach. He had been a manager of the leading Japanese pacific league baseball team Fukuoka Softbank Hawks since 1995. He also managed the Japan national team to lead the team to win the inaugural World Baseball Classic in March. It has been reported that physical and mental overwork aggravated his illness. Oh has also been known as Japan's most famous baseball batting star who broke Hank Aaron's world record in 1977 with his 868 home runs. Oh is the son of a Chinese father and a Japanese mother. Though born in Tokyo, he still carries a China republic passport. His Chinese name is Wang Chen-Chih.