JOETSU, Niigata Prefecture—Displaying a sense of humor maintained for more than a century, Chitetsu Watanabe, 112, was recognized as the oldest living man on the planet by Guinness World Records.

Watanabe, who received the world-record certificate on Feb. 12 at a nursing home where he resides, will turn 113 on March 5.

He was born in 1907 in the village of Uragawara, which is now part of Joetsu city.

When he was in his 20s, Watanabe moved to Taiwan and worked at a sugar company.

He returned to his hometown after the end of World War II and landed jobs at a prefectural government agency and other places.

After his retirement, Watanabe took up farming and continued with his hobbies, including raising bonsai and calligraphy.

His family calls him “Big Grandpa,” but the nickname now falls short.

Watanabe has five children, 12 grandchildren, 16 great-grandchildren and one great-great-grandchild.

“He’s mild-mannered and serious-minded, but he also has a sense of humor,” said Yoko, 81, wife of his eldest son. “He’s a very wonderful person.”

After receiving the certificate from a Guinness World Records official, Watanabe drew laughter by saying, “Congratulations,” to himself.

He also responded to some of the questions from reporters by laughing widely.

Perhaps unsurprisingly, Watanabe said the secret to longevity is “to laugh.”