Hanshin Education Incident
The Hanshin Education Incident (Japanese: 阪神教育事件) occurred in April 1948, when Japanese authorities, acting under the directions of the government of the United States and the Japanese Ministry of Education, closed down private Korean ethnic schools operating in Japan. This caused protests across Japan that ranged in size to up to 20,000 civilians.
Source: Wikipedia — Hanshin Education Incident (CC BY-SA 4.0)