In this sweet and funny story, Sumo Joe and his friends enjoy pretending to be sumo wrestlers. But when his little sister wants to join their boy-only game, what should Sumo Joe do? On Saturday mornings, Sumo Joe is a gentle big brother to his little sister. But on Saturday afternoons, he and his friends are sumo wrestlers! They tie on makeshift mawashi belts, practice drills like teppo, and compete in their homemade dohyo ring. They even observe sumo's ultimate rule: no girls allowed! But when Sumo Joe's little sister wants to join in the fun, Sumo Joe is torn between the two things he's best at--sumo, and being a big brother. Fists, feet, and martial art forms collide in this sweet yet spirited rhyming story by author Mia Wenjen and illustrator Nat Iwata.