Story highlights Jiroemon Kimura, the world's oldest man, has died in Japan, aged 116

The former postman retired in 1962 and attributed his long life to light eating

A rival claimant to being the world's oldest person died days earlier in China

Luo Meizhen's claims to be 127 were not officially recognized internationally

The world's oldest person has died in Japan, aged 116 -- just days after the passing of a Chinese woman with a rival claim to the title.

Jiroemon Kimura, a former postman, died of natural causes in hospital in his hometown of Kyotango, western Japan, in the early hours of Wednesday, city officials told CNN.

In December, Kimura had been recognized by Guinness World Records as the world's oldest living person, and as the oldest man whose age had ever been verified.

"I wanted him to live longer," his nephew, Tamotsu Miyake, told Japanese television network TV Asahi. "His life was respectable; I would like to say 'thank you' to him."

Kimura, who attributed his longevity to eating light, healthy meals, worked for the post office until his retirement in 1962, continuing to carry out agricultural work until the age of 90.

Only the third man in history verified to have reached the age of 115, Kimura had seven children, 14 grandchildren, 25 great-grand children and 14 great-great grandchildren.

On his passing, the mantle of oldest living person passes to fellow Japanese Misao Okawa, a 115-year old woman from Osaka.

Misao Okawa is now officially the oldest person in the world.

A rival claim

Shortly after Kimura made the record books in December, China's state news agency Xinhua reported on a woman from the southern province of Guangxi with a rival claim to being the world's oldest person.

Luo Meizhen, from the remote village of Longhong, had an official ID card and residency permit -- both issued in recent decades -- stating she was born in 1885, making her 127. In 2010, a Chinese state-sponsored research institute claimed to have verified the documents.

But her claim to record longevity was not officially recognized internationally, due to questions over of the reliability of birth records when she was born, and because of claims she had given birth to the youngest of her five children aged 61.

On Tuesday, Luo's son Huang Youhe told AFP that his mother had died at the weekend after months of illness, aged 127.

"She was a kind person, but at times had a very bad temper," said her grandson, Huang Heyuan. "She had a strong character."

A relative of Luo Meizhen, claimed to be 127, holds her portrait.

Luo, who had worked as a farmer, hailed from an area known as Bama county, which has a reputation for the longevity of its residents.

Rise of 'supercentenarians'

If accurate, Luo's 127 year lifespan would have made her the oldest person ever, surpassing France's Jeanne Calment, who died aged 122 years, 164 days in 1997.

According to a 2010 study by a German demographic research institute, the countries with the highest number of "supercentenarians" -- those aged 110 and over --are the United States, Japan, the United Kingdom, France and Italy.

The study, prompted by rising numbers of centenarians, found more than 600 supercentenarians internationally.

Researchers estimated there were more than 400 supercentenarians in the U.S., and found 78 in Japan.

As with the centenarian bracket, women far outnumbered men, with women accounting for 9 in 10 of the U.S. supercentenarians.