Denzo Ishizaki

was a Japanese educator, serving as principle of a lower secondary school in his hometown Ibaraki, and supercentenarian verified as the oldest Japanese man ever (although Shigechiyo Izumi was still believed to have been 120 years and 237 days old at the time) until either late September 2001 when Yukichi Chuganji broke his record by less than two years, "or" late October 2011 when his record was broken by Jiroemon Kimura, depending on whether his birth year was 1886 or 1884.
Age records.
Although his birth date is officially verified as October 20, 1886, Ishizaki himself claimed to be born two years earlier, and thereby ten days older than Gengan Tonaki who would have been the second-oldest living Japanese man at the time of his death on January 24, 1997, and asserted that his birth record was "delayed by two years", which would have made Ishizaki the oldest living man in Japan after Gihei Oka's death on September 28, 1991 as well as the oldest living Japanese man overall on February 16, 1992 when Russo-Japanese War veteran Mamoru Eto, who was four days younger than Gihei Oka and had emigrated to the United States, died at age 109 years, 13 days and only the second Japanese man who became a supercentenarian, after Eiju Tsuru who died on January 11, 1990.
After Gengan Tonaki's death on January 24, 1997, Ishizaki might have become the last living man born in 1884 and also the oldest living man in the world after 115-years-old Danish-born American man Christian Mortensen's death on April 25, 1998, although the American man Johnson Parks, who died on July 17 the same year, has been suggested to have been five days older than Ishizaki and another American man, Walter Richardson who died at age 113 later on December 25, is officially verified to have been less than a year older rather than over a year younger than Ishizaki.
Ishizaki was officially verified as the oldest living Japanese person, and the first man who became Japan's oldest person after Masutaro Sato who died on October 6, 1978, after Tase Matsunaga's death on November 18, 1998.
Death.
Ishizaki died of multiple organ failure on April 29, 1999 at age 114 years, 191 days "or" 112 years, 191 days and might at the time of his death have been, along with Tase Matsunaga, the third-oldest Japanese persons ever behind Tane Ikai and Hide Ohira and the youngest of only two men who became at least 114 years old, behind Christian Mortensen.
Ishizaki was succeeded as the world's oldest living man by Spaniard Antonio Urrea, as Japan's oldest living man by Sadayoshi Tanabe and as Japan's oldest living person by Kayo Fujii, although Kamato Hongo was still believed to have been older.