Jiroemon Kimura, the oldest man ever recorded, celebrated his 116th birthday Friday with a message from Japan's prime minister as health chiefs launched a study into why his home city boasts so many centenarians.
It was a busy day for Kimura, who also greeted guests including the mayor of Kyotango city and officials from the Guinness World Records.
"You give us pride and confidence in the people of Japan," Prime Minister Shinzo Abe said in a pre-recorded video greeting that marked the milestone.
Mayor Yasushi Nakayama also congratulated Kimura on reaching the ripe old age of 116, making him the current world's oldest person and the longest living man on record.
"Yes, yes, thank you," said Kimura, who is still a way off from the all-time record set by Jeanne Calment, a French woman who died in 1997 at the age of 122 which made her the longest living person in history.
Kimura, who was born in 1897 -- the same year as American aviation pioneer Amelia Earhart -- spent time in hospital after falling ill late last year, but was Friday back in the home he shares with his grand-daughter-in-law, 60.
His morning started at 7:00 am (2200 GMT) with a healthy breakfast -- a bowl of porridge with red beans, egg tofu and mashed pumpkin, a local official said.
The centenarian now has to stay in bed most of the time, but never misses his three meals a day, he said.
Kimura had seven children, 14 grandchildren, 25 great-grand children and 14 great-great grandchildren, and worked at a post office for about 40 years. After retiring he took up farming which he continued to do until the age of 90.
The centenarian does not smoke, has made it a practice to eat only until he is 80 percent full, and drinks only a "modest" amount of alcohol, local authorities and media said.
His motto in life is "to eat light and live long".
Encouraged by Kimura and 94 other people in Kyotango's 60,000-strong population who will this year be 100 years old or more, the city has launched a research project to find the secret of their longevity.
"We have a very high centenarian rate, about 2.5 times higher than the prefectural average," said a local health official.
"We don't have city-based data, but Kyotango's rate is even 1.27 times higher than Kochi prefecture, the top of all the 47 prefectures in Japan."
Health officials are researching the diet of Kimura and other centenarians, the official told AFP.
"We are interested in what they eat and how much. We are especially keen to research how much salt they consume."
The city of Kyotango, near Kyoto, is sandwiched between the Sea of Japan (East Sea) and a mountain range. It is naturally blessed with good seafood and farm products, the official said.
"We are also interested in knowing what kinds of local food they like to eat and if this helps them live so long," he said.
The city plans to compile a recipe book based on the study and unveil it at a symposium on longevity in November.
"We want city residents to know of the secrets of what enables a long life-span but also to attract tourists to this long-living city," the official said.