Moupai
Moupai 「盲牌」 is the practice of reading mahjong tiles by touch. Normally, this act utilizes the thumb and/or fingers. It is even possible to identify tiles by rubbing them on a play surface.
Drills
A number of tile reading drills can be practiced in order to become more familiar with the tiles by touch. In a sense, they can be considered as minigames on their own.