The Hibiya incendiary incident , also known as the Hibiya riots, was a major riot that occurred in Tokyo, Japan, from 5 to 7 September 1905. Protests by Japanese nationalists in Hibiya Park against the terms of the Treaty of Portsmouth ending the Russo-Japanese War escalated into a violent two-day citywide riot when the police attempted to suppress the protests. The Hibiya incendiary incident resulted in the death of 17 rioters, led to the collapse of the government of Katsura Tarō, and is considered the first event of the Era of Popular Violence. Over 2000 rioters were later arrested for their involvement, with 104 being tried and 87 found guilty.