AnimeTrove

Shunichi Domoto is a talented, sportive 5th grade boy who is used to help sport teams in his school. He enters a Yoyo duel against a bully boy called Benkei to help his friend, Beso, to get back his Yoyo which was stolen by the bully. He beated him, but after that, he meets the exceptionally gifted Yoyoer, Seito Hojoin, who beated him while he ridiculed the Yoyo game. So, Shunichi enters Japan's Yoyo championship to get his revenge from his loss with Seito. Throughout this Championship, he earns new Yoyoing Skills and meets powerful rivals.

(Source: Anime News Network)