The exact title of this movie is actually: Zhan Duan Mo Zhua, instead of Zhan Duan Mo Zhao, and the corresponding translation is: Cutting off the Devil's Claws.
This movie is based on the true story of the failed nationalist attempt to assassinate Chinese communist leaders on October 1, 1949 by firing mortar rounds into the crowd during the celebration of the establishment of the People's Republic.
The movie, however, is not 100% accurate because in order to glorify the law enforcement, the last part of the history was altered: in reality, sensing the danger, the nationalist agents abandoned the plan and fled, and police only captured all the weaponry in stored in a house next to the square, and the celebration was was delayed for 5 hours to 3:00 p.m. from the originally scheduled 10:00 a.m., but in the movie, the nationalist agents went according to plan and was captured on site, instead of later on the run as in real life.
