While Japanese tea is often thought of as just green teas, the manufacturing of black tea was introduced in Japan around 150 years ago in the Meiji period, right around the time Japan was opening to the rest of the world. Wakoucha means "Japanese black tea" in Japanese (和紅茶), but Koucha more directly means "red tea," named after its dark red color when brewed with Japanese "soft water" that is low in lime content. Koucha is a fully oxidized tea, where after the harvest, the leaves are first withered prior to processing by rolling. This process breaks the cell structure down, enhancing the oxidation process. Because black tea is new compared to the long history of green tea production, it's not widely produced and considered a specialist product.