is a type of yà Âkai (spirit or monster) from the legends of Hebei Province, China. It is also known as Sanki ().
The Japanese Edo period encyclopedia, Wakan Sansai Zue, provides a description of the Sansei based on citations from various Chinese texts. According to these sources:
The Wakan Sansai Zue also gives the Japanese kun'yomi reading kata-ashi no yama-oni (, "one-legged mountain oni") for the characters .
The Japanese artist Toriyama Sekien included the Sansei in his yà Âkai collection Konjaku Gazu Zoku Hyakki (Illustrated Supplement to the Hundred Demons of the Past and Present), depicting it holding a crab and peering into a mountain hut. The accompanying explanatory text quotes the description found in the Wakan Sansai Zue, noting features such as its origin in Anguo County (referred to by the old Japanese term for China, Morokoshi), its alternative name 'Sanki', its habit of stealing salt, and its diet of crabs.
Due to its inclusion in Sekien's influential work, some later Japanese yà Âkai literature, particularly from the Shà Âwa and Heisei eras onwards, have presented the Sansei as if it were a native Japanese yà Âkai, rather than one originating in China. Some of these derivative descriptions mention it appearing at mountain huts specifically because it wants salt, while others claim it holds dominion over the animals of the mountains.