Sencha, Genmaicha, and Hojicha are all different kinds of Japanese green tea. Depending on how the leaves are processed, there are distinct differences in aroma, flavor, and caffeine levels.
Sencha. The most common popular green tea in Japan. Contains green tea leaves that are steamed and rolled. Contains the most caffeine with a bright green hue.
Genmaicha. Combines green tea leaves with roasted, popped brown rice, about a 50-50 ratio. Low caffeine with a toasted, savory aroma.
Hojicha. Green tea leaves that are roasted. Low caffeine with a nutty aroma.