Chitetsu Watanabe has created a World record as the oldest man. At the age of 112 years, the Japanese man has claimed that smiling is the key to longevity. The oldest man's title was officially given at his nursing home in the city by the management of the Guinness World Records. Chitetsu Watanabe was born on March 5, 1907, in Niigata, north of Tokyo. It is said that Japan has been home to several people recognized as among the oldest humans to have ever lived.