On 2 December 2011, upon the death of 115-year-old Chiyono Hasegawa, Kimura became the oldest living person in Japan and the third oldest living person in the world behind Americanwomen Besse Cooper and Dina Manfredini, both of whom died in December 2012, whereafter Kimura also became the oldest living person in the world, and also the oldest man ever after breaking Danish-born Americanman Christian Mortensen's record, and later on 19 April 2013, his 116th birthday, the first and only verified man as well as only the 7th verified person to become at least 116 years old. Less than 5 weeks later, after 113-year-old James Sisnett's death on 23 May, Kimura became the last living man in the world born in the 19th century, after already being the last living Japanese man since 111-year-old Tanekichi Onishi from Hokkaido, who was just a week older than Sisnett, died on 11 September 2011, and even the last living person born in 1897 since Japanesewoman Koto Okubo, who was the oldest living woman, died at age 115 years, 19 days on 12 January 2013.