The revised curriculum guidelines were fully implemented in junior high schools starting in 2021, and in high schools starting in 2022. In the case of history education, a new compulsory subject “Modern and Contemporary History” was established in high school, and education that emphasized modern and contemporary history continued from the social studies taught in junior high school. For students who want to study Japanese history more seriously, there is also a class subject called “Advanced Japanese History” that covers everything from ancient times to modern history. Therefore, the opportunity to learn about pre-modern history was maintained. However, the purpose presented there was to answer questions that give a general perspective of the times, while understanding the changes that occurred at the turn of the era, based on the modern and contemporary history that you will learn first in “Modern and Contemporary History”. If so, as a common problem from ancient times to modern society, will we have the opportunity to learn ‘why a particular era or system has continued for so many years?’ It is desirable to continue developing teaching materials suitable for high school students to help them understand the importance of exploring this question. Based on the awareness of issue, this paper presents the problem of the information network formed originally by the feudal clans of the Seto Inland Sea in Edo period. Through this explanation, I would like to make them think about both its question and conversely ‘Why did the administration that was so prosperous perish?’ Considering these two questions is important for students learning the characteristics of national systems correctly from a long-term perspective.