The High Treason Incident (Taigyaku Jiken) was an anarchist plot to assassinate the Meiji emperor, one that led to the 1910 mass arrests of a number of socialist activists and concluded with 26 people being charged. Twelve of these were hanged.
According to historian F.G. Notehelfer, the plan — as outlined by one of the perpetrators — was to bomb an imperial procession, then to start riots, destroy prisons, release prisoners, kill ministers, and attack government offices.
It was the Meiji government and not the Meiji emperor that was the target of the attack.