Dongmingji 洞冥記, full title Han Wu dongmingji 漢武洞冥記 "Records of the darkness in the cavern of Emperor Han Wudi", is a collection of phantastic stories traditionally attributed to the Han period 漢 (206 BCE-220 CE) scholar Guo Xian 郭憲 who was among the scholars contributing to the downfall of the usurper Wang Mang 王莽 (r. 8-22 CE). According to the imperial bibliography Jingjizhi 經籍志 in the official dynastic history Suishu 隋書 the author is called Master Guo 郭氏, while the first bibliographic mentioning of the name Guo Xian is only to be found in the bibliographic treatise in the dynastic history Jiutangshu 舊唐書. The Dongmingji might in fact have been compiled during the Southern Dynasties period 南朝 (420~589). The length ranged between 1 and 4 juan "scrolls". The received version is 4 juan long.
The title of the book is derived from a story which says that the Daoist master Dongfang Shuo 東方朔 dug himself into the innermost darknesses (i.e. obscurities or secrets) of the study of the "Way" (dao 道) in order to enlighten Emperor Wu of the Han dynasty 漢武帝 (r. 141-87 BCE). The Dongmingji contains stories of immortals and Daoist scholars that are able to exhibit supernatural powers and that appear to commoners in strange appearings. It is very similar to the collection Shenyijing 神異經. A lot of the stories are very famous and were often quoted by later authors, like the story of Xi He 羲和, the story of the three-legged bird (sanzu niao 三足鳥), or a green dragon holding a candle (qinglong xian zhu 青龍銜燭). The book was quite probably compiled during the Southern Dynasties period 南朝 (420~589).
The Dongmingji is included in the reprint series Han-Wei congshu 漢魏叢書, Longwei mishu 龍威秘書, Shuofu 說郛, Gujin yishi 古今逸史, Zishu baijia 子書百家, Shuoku 說庫, Baoyantang miji 寶顏堂秘笈, Wuchao xiaoshuo 五朝小說 and the Siku quanshu 四庫全書.