In the Edo period (1603-1867), marijuana was known as one of the “three herbs” along with indigo and safflower, and was cultivated throughout Japan as a useful crop. For example, from Chapter 1 (Lesson 1) of the “Elementary School Readers’ Book for Senior High School Students, Vol. 2,” published in 1897, it is written that Amaterasu Omikami wove the loom himself and that Emperor Jimmu sent Amatomikoto to Shikoku and Tōgoku to plant hemp and kozo (paper mulberry trees). The second chapter, “Hemp and Kozo,” describes hemp as a plant, how it is grown, and its products, such as mosquito nets. Children in those days learned about marijuana in school and had more knowledge than we have today. Many children probably saw actual marijuana. In Kanuma City, Tochigi Prefecture, which has been in existence for more than 400 years since the Edo period, a large field of marijuana is still a place for children to play hide-and-seek, and for adults, it is a field crop no different from radishes and carrots.