Taigyaku Jiken is a collective term referring to the incidents in which perpetrators were prosecuted for high treason, which was a crime to inflict or try to inflict harm on Emperor, Empress or Crown Prince, as defined in the article 116 of the former Penal Code enforced in 1882 and the article 73 of the Penal Code enforced in 1908 after the enactment of the Constitution of the Empire of Japan (the article was eliminated in 1947).
1882年に施行された旧刑法116条、および大日本帝国憲法制定後の1908年に施行された刑法73条（1947年に削除）が規定していた、天皇、皇后、皇太子等を狙って危害を加えたり、加えようとする罪、いわゆる大逆罪が適用され、訴追された事件の総称。