What is the difference between Tai Chi Chuan and Taijiquan?
None. They are different romanization methods of writing Chinese: Wade-Giles ( Tai Chi Chuan, Chi Kung, Hsing-I, Pa Qua Chang, etc) and Pinyin (Taijiquan, Qigong, Xing-Yi, Baqua Zhang, Etc.). Initially Wage-Giles was more used in the West, but recently Pinyin, which is used in teaching Mandarin, is increasing in use.