Li Mengrui (李夢瑞), whose style name was Shao'an (少庵), was a native of Nancaiyuan Village, Haiyang County, Shandong Province (山東省海陽縣南才苑村). When he was young, he moved to Beijing to study and work at Shandong Restaurant (山東飯館). At the age of 20, he became a disciple of 2nd generation baguazhang exponent Liang Zhenpu (梁振蒲). He later became sworn brothers with Li Wenbiao (李文彪) (Cheng Tinghua's (程廷華) disciple), Liu Dongchen (劉棟臣) (Yin Fu's (尹福) disciple), and Big Broadsword Wang Wu (大刀王五) (i.e. Wang Zhengyi (王正誼), Six Combinations Boxing disciple of Li Fengyan (李鳳崗)); of these, unfortunately, both Li Wenbiao and Wang Zhengyi were killed during the Boxer Rebellion in 1900. Like his teacher Liang Zhenpu, Li Shao'an was good at Daishou (a special technique of the bagua school), so people called him Iron Arm Li #4 (鉄胳膞李四). In 1948 he returned to his hometown and worked as a farmer. Unfortunately, Li Shao'an never took disciples, although he sometimes taught others in the bagua school.
Li Shao'an, Guo Gumin (郭古民), and Li Ziming (李子鳴) were the most famous of Liang Zhenpu's disciples, and the three often trained and studied baguazhang together.