Dragon Ball Volume 3 by Akira Toriyama

With the Dragon Balls gone and Bulma's summer vacation over, Goku goes to the remote house of the Turtle Hermit, Kame-Sen'nin, to be trained in the martial arts. There, the girl-ogling old master promises to teach Goku everything he knows...and prepare him for the Tenka'ichi Budokai, the great tournament to determine the Strongest Fighter in the World! But Goku's fellow student, the Shaolin monk Kuririn, isn't above cheating to be the best. Can the two of them get along as they undergo the strangest martial arts training ever?