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Seisen International School is a private Catholic school in Tokyo serving the international community, with a total K–12 population of about 700 students representing over 40 nationalities. Teaching is in English, and the school encourages students to speak English within the school. Seisen describes itself as an International Baccalaureate Continuum school, offering Montessori and the IB Primary Years Programme in Kindergarten, IB PYP in Elementary, IB MYP in Grades 6–10 and the IB Diploma Programme in High School. Facilities on the campus include science labs, a design tech room, music rooms, a drama room, library media centers, a chapel, a gymnasium and a field and tennis courts. Seisen also highlights service and leadership opportunities for students as part of school life.