Asked about the secret to longevity, Watanabe has this advice: Don't get angry and keep smiling.
He was born on March 5, 1907, and is the oldest brother to seven siblings.
Kane Tanaka, a 117-year-old Japanese resident of Fukuoka Prefecture, is recognized by Guinness World Records as the world's oldest living person following the death in July 2018 of another Japanese woman, Chiyo Miyako from Kanagawa Prefecture, at 117.
"Watanabe, who lives in a nursing home in Niigata, received an official certificate from Guinness World Records, " the organisation said in a statement.
That's the age of Chitetsu Watanabe, who has just been declared the oldest living man by Guinness World Records.
After graduating from agricultural school, Chitetsu became a staff member of Dai-Nippon Meiji Sugar and moved to Taiwan to help conclude sugar cane plantation contracts there.
"Both Chitetsu and Tetsuo told me that getting to places and sourcing food was a struggle".
Kane Tanaka, who is now the oldest living woman, celebrated her 117th birthday in January.
The previous record holder was Masazo Nonaka.
But Mr Watanabe and his family were tough, too: the Niigata native got back into the agriculture industry, and even after he retired he built a new family home with his son where he farmed all sorts of fruits and vegetables in the garden- until he was 104 years old!
Until about a decade ago, Mr Watanabe used to grow bonsai trees and had a collection of about 100 which he used to exhibit.
During his 18 years in Taiwan, Chitetsu married Mitsue and four out of five of their children were born there. He's also caring. When I was working on my patchwork hobby, he was the one who praised my work the most.
The current title is held by another Japanese man, Jiroemon Kimura, who was 116 years old when he passed away.