Satori (覚?, "consciousness") in Japanese folklore are supernatural monsters ("yōkai") said to live within the mountains of Hida and Mino (presently Gifu Prefecture), and able to read people's minds.
People are said to meet them while walking along mountain paths or resting in the mountains. Upon reading a person's mind, the satori would say the person's thoughts aloud faster than a human could. There is also a theory that they are the child incarnations of mountain gods who have come to ruin and turned into a yōkai form.
They would appear before people at mountain huts, and are even said to try to eat and kill if they have a chance, but if something unexpectedly strikes the satori, they become striken with fear due to fact that something unexpected occurred, and run away. There is also a theory that they do not present any danger to people and would not dare to harm those who work on the mountain, allowing people to coexist with satori.
A satori is depicted in Toriyama Sekien's Konjaku Gazu Zoku Hyakki, but since this was modeled after the yamako (玃) in the Wakan Sansai Zue and other works, and since it even said, "there are yamako (玃) deep in the mountains of Hida and Mino" in the text along with it, it is said that Toriyama Sekien gave it the name "satori" since they are able to read (satoru) people's minds. The yamako was an ape man from Chinese legends, but in the Wakan Sansai Zue, it was an animal that read people's minds in Hida and Mino, and since the character 玃 can also be pronounced "kaku," the character 覚 (also "kaku") was used as one that fit for a replacement, which was later misread as "satori," so there is the interpretation that this is what gave birth to the legend of "satori" as a different kind of yokai than the yamako. There is also the theory that satori are based off the yamabiko found in the Konjaku Gazu Zoku Hyakki and the Hyakkai Zukan and other collections, but according to the folkloristician Kunio Yanagita, from his work "Yokai Dangi," the folklore that satori would read people's minds, and the legend that yamabiko would imitate people's voices have the same origin.