In this paper, we will examine the current status of questions related to Yi Sun-sin in various tests conducted in modern Japan and their meaning. Among them, we will examine the teacher certification exam conducted by the Ministry of Education, various school entrance exams and recruitment exams and reference books related to them. Through this, we can find out at what time the question regarding Yi Sun-sin was raised and what meaning it has. Also, we can see how much knowledge about Yi Sun-sin was required for people who had a certain level of culture. For secondary school history teachers, Yi Sun-sin was a person whose life and activities they needed to know in detail, and for test takers and those preparing for various recruitment exams, Yi Sun-sin was a person they needed to know about while studying the Imjin war. In other words, for people with a secondary school education or higher, Yi Sun-sin was a figure they should know at the level of common sense.