The Long Zii Tong was a Chinese-American tong association and criminal organization that was active in Chinatown, San Francisco during the 1870s. Led by Long Zii, the tong was one of the most powerful during that era, rivaling the Hop Wei Tong. In 1878, the gangs clashed over the opium trade in what escalated into the Tong Wars; Mai Ling seized control of the tong after murdering her husband Long Zii and blamed his death on the Hop Wei, but her reputation deteriorated, her lieutenant Li Yong left her, and her gang was nearly destroyed by the Hop Wei.