There is a real, geographical Ruo Sui ( also Etsin Gol or Ruo He or Ejin River). This Ruoshui (Weak River) is not identical with the mythological Weak River. Are there historical points of tangency? What is the relationship between the two? One major difference between the modern river and the mythological river is that the modern river of that name was named for its seasonal weak flow in its lower reaches: the mythological Weak River was named for the inability of the liquid substance constituting it to float any objects. Another difference is that the geographical river rises as the Heishui (, black water) on the north slopes of the Qilian Mountains, a major river system of northern China, then flowing approximately from its headwaters on the northern Gansu side of the Qilian Mountains, on a spur of the Kunlun range, north-northeast into the endorheic Ejin Basin in the Gobi Desert, forming one of the largest inland deltas or alluvial fans in the world, its drainage basin covering about in Gansu and Inner Mongolia: on the other hand, the mythological Ruoshui River circles Kunlun and is the scene for all sorts of activities by deities, immortal, would-be immortals, and so on, and generally exists in an alternate reality of culture. However, both Ruo Shui rivers are directionally located in a somewhat northern and western way.