He graduated from the College of Science at Osaka University with a degree in mathematics and taught high school mathematics in his home town of Osaka.
[1] In 1954, his son, Takeshi, performed poorly in a Year 2 mathematics test.
Prompted by his wife, Teiko, Toru closely examined Takeshi's textbooks and believed they lacked the proper opportunity for a child to practice and master a topic.
By the time Takeshi was in Year 6, he was able to solve differential and integral calculus.
[1] Toru Kumon died in Osaka on July 25, 1995, at the age of 81 from pneumonia.