The purpose of this study is to clear Hiraku Tohyama's thought of education  and to get some suggestions to solve the problem that is called the decrease in scholastic ability. Hiraku Tohyama (1909-1979) was a mathematician and professor of Tokyo  lnstitute of Technology. He was also the first chairman of the Association of Mathematical lnstruction (AMI).  He strived to reform the mathematical education from elementary to higher education.
 His movement of mathematical education reconstruction started in l951. He was famous for "Theory of Quantity" and "Suido-hoshiki (the Water Supply Method)" that is the system of calculation with figures.
 He tried to modernize mathematical education, make it consistent from elementary to high ereducation,  and make the scientific method of mathematic education.
 In those days there were many remedial students who couldn't master curricula which followed l960' s American curricula which  aimed at modemization of education of science and mathematics. He claimed that "Enjoyable lessons motivate students to study voluntarily. Tohyama denounced unitary evaluation because it was the point system of every student's  aspect that involved something such as his or her attitude not to be objectively evaluated. But unitary evaluation was adopted and used entrance  examination for high school in Japan. Students who wanted to enter high school as his or her wish had to get higher marks. Some students couldn't get high  points dropped out. He indicated that students' motivation reduced with pressure of competition. In l970' s he advocated that school must get rid of competitive education and aim to make students have "Kan", which is like their view of life and the world.
 This research is aiming to clear the concept of "Enjoyable lessons", and the reason why Tohyama claimed the education for fostering  "Kan". First,  I tried to explain circumstances around mathe matical education and Japanese students of l960's and 70's.  Second l referred to the theory of flow (Mihaly Cskszentmihailyi) in order to interpret "Enjoy", which was not popular in Japan during Tohyama' s lifetime. Third, I researched the situation of acceptance to his opinion..

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