Widely known as Japanese delicacy around the world, matcha's origin is actually from China. Then, probably foreigners love matcha flavor more than local Japanese. Especially matcha is recognized as local specialty of Kyoto, including Uji city of Kyoto prefecture.
According food labeling regulations of Japan, unrubbed green teas which are harvested under covered field are dried and grounded by tea mill stone or other type of mill. However, 2/3 of matcha which are sold in Japan seems to be not produced by above method.
Although authentic matcha is a hot beverage, it is not easy to enjoy matcha during your stay in Japan. On the other hand, matcha flavor can be enjoyed throughout Japan especially between spring and summer. Typical products which have matcha flavor are ice cream, chocolate and parfait.