The Yellow River Map, Scheme, or Diagram, also known by its Chinese name as the Hetu, is an ancient Chinese diagram that appears in myths concerning the invention of writing by Cangjie and other culture heroes. It is usually paired with the Luoshu Squarenamed in reference to the Yellow River's Luo tributaryand used with the Luoshu in various contexts involving Chinese geomancy, numerology, philosophy, and early natural science. Geographical background The Yellow River (Chinese: Huang He) flows from the Tibetan Plateau to the Bay of Bohai over a course of , making it the second-longest river in Asia and the sixth-longest in the world. Its ancient name was simply He before that character was broadened to be used in reference to most moderately sized rivers. The River Map has thus always been understood to be particularly in reference to the Yellow River and sometimes taken as a diagram of its course or the forces acting upon it. Astrological background The concept of the Yellow River Map has a contextual apparatus associated with ancient Chinese cosmology. Various myths or legends are connected with the idea of mapping, involving correspondences between the earth, the sky, and/or abstract diagrams. The idea of a simple division of a flat/square earth into the very basic 3x3, (9-square) grid is historically attested in literature as early as the Tian Wen'''s "Heavenly Questions", together with a suggested corresponding mapping solution for a round heaven/the sky (Hawkes, 136–137 [notes to Tian wen]). This text from the Chu Ci dates to pre-221 BCE. This basic grid is associated with the plan of Yu to control the Great Flood of China. Legendary accounts Myths of the Yellow River Map go back to earliest stages of the recorded history of Chinese culture. Fu Xi Fu Xi or Fuxi was a half-snake deity and protoplast who has appeared with his sister Nüwa in accounts of the creation of humanity and invention of civilization since at least the Zhou dynasty. Among the stories told about him is one in which, inspired by spider webs and other natural phenomena, he created the River Map and then used it to devise the trigrams that comprise the later I Ching. Great Flood Yellow River floods were a constant occurrence throughout ancient, medieval, and early modern Chinese history, sometimes covering entire provinces and even shifting between the north and south sides of the Shandong Peninsula. The Great