The Willow Pattern is a gong'an detective novel written by Robert van Gulik and set in Imperial China (roughly speaking the Tang Dynasty). It is a fiction based on the real character of Judge Dee (Ti Jen-chieh or Di Renjie), a magistrate and statesman of the Tang court, who lived roughly 630–700. As the author says in a postscript, the use of the Willow Pattern as a motif in the book was a conscious anachronism. The book features 15 illustrations by the author.