style () of Yang Luchan (1799–1872) Wu Hao style () of Wu Yuxiang (1812–1880) Wu style () of Wu Quanyou (1834–1902) and his son Wu Jianquan (1870–1942) Sun style () of Sun Lutang (1861–1932) The most popular is Yang, followed by Wu, Chen, Sun and Wu/Hao. The styles share underlying theory, but their training differs. Dozens of new styles, hybrid styles, and offshoots followed, although the family schools are accepted as standard by the international community. Other important styles are Zhaobao tàijíquán, a close cousin of Chen style, which is recognized by Western practitioners; Fu style, created by Fu Chen Sung, which evolved from Chen, Sun and Yang styles, and incorporates movements from Baguazhang (Pa Kua Chang); and Cheng Man-ch'ing style which simplifies Yang style. Most existing styles came from Chen style, which had been passed down as a family secret for generations. The designation internal or neijia martial arts is also used to broadly distinguish what are known as external or waijia styles based on Shaolinquan styles, although that distinction may be disputed by modern schools. In this broad sense, all styles of t'ai chi, as well as related arts such as Baguazhang and Xingyiquan, are, therefore, considered to be "soft" or "internal" martial arts. United States Choy Hok Pang, a disciple of Yang Chengfu, was the first known proponent of tai chi to openly teach in the United States, beginning in 1939. His son and student Choy Kam Man emigrated to San Francisco from Hong Kong in 1949 to teach t'ai-chi ch'üan in Chinatown. Choy Kam Man taught until he died in 1994. Sophia Delza, a professional dancer and student of Ma Yueliang, performed the first known public demonstration of tai chi in the United States at the New York City Museum of Modern Art in 1954. She wrote the first English language book on t'ai-chi, "T'ai-chi ch'üan: Body and Mind in Harmony", in 1961. She taught regular classes at Carnegie Hall, the Actors Studio, and the United Nations. Zheng Manqing/Cheng Man-ch'ing, who opened his school Shr Jung t'ai-chi after he moved to New York from Taiwan in 1964. Unlike the older generation of practitioners, Zheng was cultured and educated in American ways, and thus was able to transcribe Yang's dictation into a written manuscript that became the de facto manual for Yang style. Zheng felt Yang's traditional 108-movement form was unnecessarily long and repetitive, which makes it