Jinenjo is a kind of wild mountain yam that grows deep in the mountains. It is very thick when grated, very nutritious, and was originally sold for high prices. The person who pioneered methods for growing this yam in farm fields was a Yanai City local, Toshio Masada. His discoveries made it possible to grow jinenjo in fields today. Yanai City enterprises grow jinenjo yams and the seed yams needed for production, and supply the entire country.