Sencha accounts for the largest portion of Japan's tea production and unlike Matcha and Gyokuro, it is grown in full sunlight. Sencha is steam treated, sealing in the flavor and stopping the oxidation. The leaves are dark green and needle-shaped. The deeper the green of the leaves, the higher in grade. The flavor, color and quality of Sencha depend not only on region but also the season in which the leaf was harvested and the processing method used. Leaves that are harvested late are bitterer, have generally less aroma and the leaves are generally less uniform. There are many grades of Sencha.