This research is to look into the phenomena of the fortified borderless characteristics in the classroom-theatre. Students play both roles as performers and spectators, which is a peculiarity of classroom-theatre. Another features differing the classroom-theatre from performances in the theatre are short-term preparation, and untrained amateur actors. Classroom-theatre is a part of the curriculum at school, and short amount of time is alloted. Consequentially writing a text, rehearsing, and setting a stage are processing at roughly the same time because of the time lack. This causes poor quality of acting in the performance and interrupts to concentrate on acting. The last feature focused is a unsettled space for the theatre. The stage in the classroom-theatre is the classroom itself. This means that there is no physical division between classroom as a stage and classroom as a living space. As a result, great and small real life events may often interrupt the performance. These traits are blended and strengthen the characteristics of the theatrical borderless in the classroom-theatre. The fiction of the play is mixed up with the reality of the classroom on account of the unstable theatre space. In addition, the border between performers and audience is blurred. The spectators feel performers as more friends rather than actors when these cannot keep focusing in acting. The fortified characteristics of theatrical borderless might lower the level of completion as a performance which is not crucial in the classroom-theatre. Active interference between fiction & reality, and between acting & spectating that is sprung from the borderless characteristics of classroom-theatre can promote to feel sympathy more deeply, which helps to learn the subject more sensuously.