My Name Is Teppei Ore wa Teppei

Teppei, brought up by his father in the mountains, is an energetic boy who is as tough as weeds and acts as free as a bird. His life changes completely when he enrolls in high school, the first school he has ever attended. Despite his eccentric behavior and being a constant source of troubles, he is soon recognized for his talent in sports—especially in Kendo (the Japanese swordplay art)—and becomes the school's hero. (Source: Nippon Animation)