Is the history of surgery an independent field of research into Chinese medicine? The historical sources are fragmentary, scattered, and riddled with fantastical descriptions. To unlock the references made in sixteenth-century texts to the use of silk thread to stitch up damaged tracheas, which are taken to be factual, the author of this article proposes a research method he calls "investigating precedents." Every independent reference to this kind of surgery must be dealt with separately. We cannot assume, a priori, that a reference to what must have been a very sophisticated procedure is either a far-fetched interpretation or a fabrication, nor should we evaluate it according to modern surgical criteria. Apart from extraordinary cases, we have no records of other types of surgery in the history of Chinese medicine, therefore we must find a method that allows us to investigate these records on their own terms.