This article deals with thunder magic during the time of emperor Sung Hui-tsung (r.1100-1126), focusing on theoretical expositions (Discourse on the Thunders) by Wang Wen-ch'ing (1093-1153). Thunder magic is a general term that summarises a large array of exorcist practices in Heavenly Masters Taoism (Cheng-i tao). Court Taoists like Wang Wen-ch'ing sublimated with literary means such practices that in a stunning way resembled shaman methods that were designed to avert disasters like droughts. Wang Wen-ch'ing used the Book of Changes and some astronomical notions in order to formulate his Discourse on the Thunders, describing the workings of the cosmos that set the frame for ritual interferences in terms of Taoist thunder magic. The article shows the actual application of these theoretical notions in religion. The author translates and interprets relevant texts, which all are taken from the canonical collection Tao-fa hui-yüan. These texts show the way Wang Wen-ch'ing identifies the cosmos with divine forces that can be addressed and administered by thunder rituals. Taoist priests even today know and use such ritual methods, which prove thunder magic to be a living religious tradition.