Higashikan, a genius young mahjong player, is the grandson of Higashi Ankou, a professional mahjong player who was said to be the one to compete for the throne. Akira is a middle school student who is an excellent mahjong player, but at school he is ridiculed and called ``the weakest guy in the class.'' If the opponent is weak, Kai won't be able to demonstrate his ability at all. On the other hand, when facing a professional mahjong player, Kai becomes a mahjong demon...in other words, he fights as a mahjong demon. And when he is in a pinch, Kai...! ? Volume 1 depicting a young boy's passionate battle!!