"Eucommia tea," "tochu-cha." とちゅうちゃ、杜仲茶。
Tochu-cha is tea made from the leaves of the Eucommia tree, in China called Duzhong. The Duzhong has long been used in traditional Chinese medicine. The bark of the 15 meter high tree is, for example, believed to alleviate lower back pain and aching knees.
The deciduous leaves contain some rubber (it comes out when you fold them), but are also used to brew tea. Tochu tea is supposed to help lowering high blood pressure, slim down and cleanse the body. It also has an interesting taste.
The tea was first made popular in Japan by Hitachi Zosen, a shipbuilding company on the path of diversification. Hitachi Zosen caused a small boom with tochu-cha in the nineties. Afterwards, the company sold the product rights of this health food to Kobayashi Pharmaceutical, who is now the main manufacturer of this type of tea in Japan.
Duzhong trees have to be cultivated, they do not grow in the wild anymore, but they have been succesfully imported to Japan and planted in the Ina area of Nagano Prefecture.