The May 15 incident occurred on 15 May, 1932. The then Prime Minister of Japan Inukai Tsuyoshi was killed.

Eleven young Naval Officers, most only just turning twenty, attempted a Coup d'état, attacking the prime minister's residence. This act was one of the main reasons Japan's party-based government ended. After this the military became an influential voice in the ruling of the country until the end of the Second World War. The eleven were court martialed and at the end of the trial a petition containing 350,000 signatures was collected in favor of a reduction of the sentence from death. 11 severed fingers were also sent to the court house as well as it was traditional in ancient Japan to cut off the little finger of the left hand as a punishment for a crime. This ensured that the pinky-less criminal would be unable to hold a sword properly.