The five distinctive marks on this vase are Daoist talismanic diagrams or insignia known as the "True Forms of the Five Sacred Mountains". They refer to the mountains Taishan, Hengshan (near Beijing), Huashan, Songshan and Hengshan (near Changsha). These diagrams were engraved on stone stelae preserved at the sacred mountains and other sites and can be traced back reliably as far as the Song Dynasty, though they are probably of even greater antiquity. They were printed on pieces of paper, too, and carried on the body as talismans. As the mystical images of the mountains, they were believed to possess supernatural powers that were associated with the mountains themselves. Refer to Kiyohiko Munakata, Sacred Mountains in Chinese Art, Krannert Art Musuem of the University of Illinois, 1991. See also, Edouard Chavannes, Le Tai Chan, Paris, 1910, figs. 55, 57 and 58

The design of the three necks of the flask, with two smaller ones flanking the larger central one, is suggestive of the form of the character shan, or mountain

The diagrams, while fairly accurately reproduced, do not appear in the standard arrangement, where the northern mountain is in the upper left corner and the southern in the lower right. The northern mountain is, instead, in the lower left, with the southern directly above