Tenryū is the westernmost of Shizuoka's three mountainous tea-growing regions, with tea fields dotting the mountains that flank the Tenryū River and its tributaries. Like other mountain teas (山茶 – yamacha) from Honyama and Kawane, Tenryū tea is praised for its transparent and elegant taste, deriving from the mineral rich soil and the subtle, natural shade of fog and mountains. Compared to the Honyama and Kawane teas, Tenryu fields are typically planted further up the mountains, at higher altitudes and nestled away from pollution. Typically unshaded and lightly-steamed, Tenryu sencha is known for its clear, crisp taste, and distinctive aroma, known as yama no kaori (山の香) or mountain aroma.

Located deep within the mountains, the Isagawa valley extends off of the Fudou river, which feeds into the Keta river (a major tributary of the Tenryu river) and is part of the Haruno subregion of Tenryū. Its relative isolation remote location makes Isagawa the ideal place for organic tea cultivation as there is no risk of runoff from neighbouring farms. The organic tea plantation here spans 20 hectares running from 300-600m in altitude. The cooler temperatures and rich soils afforded by this high altitude mean no pesticides or chemical fertilisers are necessary. In addition to the natural shading that mountain plantations enjoy, the high altitude also slows the tea plant’s growth, resulting in richer teas.