The 1952 “Bloody May Day” incident involved clashes in Tokyo, Japan. The confrontation took place on May 1, 1952, in Kokyo Gaien National Garden, the plaza outside the Imperial Palace.
The protest followed the end of the Allied occupation and the entry into force of the U.S.-Japan Security Treaty. Labor activists, students, Communist Party supporters, and Zainichi Korean activists opposed the treaty and attempted to occupy the traditional May Day gathering place, despite a government ban on public assemblies there.
Police moved to clear the plaza after protesters refused to disperse. The resulting melee involved stones, clubs, bamboo weapons, Molotov cocktails, pistols, tear gas, and batons. Police gunfire killed two protesters and wounded 22; overall, roughly 2,300 protesters and police were injured, and 1,232 people were arrested. Osaka and other Japanese cities also saw later unrest, but the incident known specifically as Bloody May Day occurred in Tokyo.