Abstract
LINE is one of the most popular smartphone application to enable users communicate with each other using text and stamps. The young generation, especially, are familiar with these application so that 77-87% of 15-19year-old users use LINE every day to communicate with friends, while LINE is often refered whenever troubles like bullying or luring. In this paper we introduce our trial to developed MANGA textbook for junior and senior high school students to learn about online communication and show the results of MANGA-class in junior highschool.