Sogen Kato's mummified corpse was found in his bedroom

Sogen Kato was thought to have been Tokyo's oldest man until July 2010, when his mummified corpse was found in his bedroom.

It was concluded he had likely died in November 1978, aged 79, and his family had never announced his death in an attempt to preserve his oldest man record. 

Relatives had rebuffed attempts by ward officials to see Kato in preparations for Respect for the Aged Day later that year, citing various reasons from him being a "human vegetable" to becoming a Sokushinbutsu (practice of observing austerity to the point of death and mummification.) 

The cause of death was not determined due to the state of Kato's body.

The discovery of Kato's remains sparked a search for other missing centenarians lost due to poor record keeping by officials. 

A study following the discovery of Kato's remains found that police did not know if 234,354 people over the age of one hundred were still alive. 

Poor record keeping was to blame for many of the cases, officials admitted.