I was reading a review of a book about Dowager Empress Cixi where the author says "After 1850 the Qing imperial government was faced with the challenge of the Taiping rebels, whose blend of Christian, Manichean and Chinese folk influences". I knew about the Christian and folk influences but as far as I knew Manichaeism was pretty marginal in China by this period, so was there any influence?
A very good question. The answer, as far as I can tell, is 'at most very slightly, and only indirectly.'
Vincent Shih's The Taiping Ideology (1967) has an absolutely comprehensive list of influences on Taiping doctrines and beliefs, but for the most part Shih only mentions Manichaeism in the context of Song Dynasty uprisings in his discussion of pre-Taiping sectarian revolts. The one time Manichaeism is brought up in relation to the Taiping is in the case of a Qing official who mistakenly believed the Taiping to be taking cues from the Manichaeans in terms of their religious writings.
So, how did Manichaeism crop up in this review? My suspicion is that Crossley may have got the Taiping muddled with the White Lotus Society, another syncretised sect that itself launched a major revolt about fifty years earlier in 1796. While I am no specialist in its beliefs, it appears to be generally accepted that the White Lotus, which formed in the early 14th century, combined the moral philosophy of Mahayana Buddhism, the mythology of popular Daoism and aspects of the millenarian creed of both Maitreya Buddhism and Manichaeism – the Buddhist deity Maitreya ushering in the age of peace and prosperity, and a Manichaean Prince of Light triumphing over the darkness. In all likelihood Crossley probably mixed up the syncretic elements of Taiping millenarianism with those of the White Lotus, and that is where the Manichaean comment came in.
For this answer, aside from Shih's The Taiping Ideology I referred chiefly to Susan Mann Jones and Philip A. Kuhn's 'Dynastic Decline and the Roots of Rebellion', in The Cambridge History of China volume 10.