Any examples of guys who learned boxing themselves growing up before they turned pro but then joined a trainer for the pros or those who trained themselves as a pro? Julio Cesar Chavez learned boxing himself and then got himself a trainer in Cristobal Rosas when he was becoming well established as a pro. I think Lineal LWW champ Koichi Wajima, with his famous Frog Punch, is the only one I know who didn't box until he was 25 years old, and he taught himself to box. Is there anyone who fits into this category? Dmitry Pirog counts to an extent. He went through the Russian amateur system and had amateur trainers, he then had a trainer in the pros...but Pirog did create his own style by watching youtube videos.