Gyokuro is one of the most expensive types of sencha available in Japan. The name comes from the product name given to the tea by the Yamamotoyama Tea Company. The tea was first discovered by Yamamotoyama's sixth owner, Yamamoto Kahei, in 1835 (Tenpō year 6). The process was completed by another manufacturer at the start of the Meiji period.
The greatest appellation of gyokuro is Yame in Fukuoka Prefecture in terms of both quality and quantity. More than 40% of gyokuro is produced in Yame, and in the national tea jury in August 2007, gyokuro of Yame held all the ranking positions from first to 26th as the best gyokuro. TheUji district is the oldest gyokuro-producing region in Japan.