One of the surviving copies of the Lanting ji preface is said to be a copy by Feng Chengsu of the Tang dynasty. The surviving ink copies of the Lanting Preface are most famous for their "Shen Long Ben", which was named "Shen Long Ben" because of the small seal of the year of Li Xian, Emperor Zhongzong of Tang, at the beginning of the volume, and because the seal of Shen Long was only the left half, or "Shen Long Half Seal Ben ", to distinguish it from other copies. This copy is now in the Palace Museum, Beijing.