Chibi is part of the kids gang that follows Joe around. Chibi is often forgotten due to how he has very few lines despite appearing throughout the manga. 
He is also rarely shown in the anime and only appears in the very first episodes of the kids gang. 

He has 2 cameos in Ashita no Joe 2, he first appears when he receives a present from Carlos when he's dressed as santa. His second appearance is in episode 43 when he's shown very briefly in the background of the flashback when Joe met Danpei for the first time. 

Joe Yabuki is a troubled young man who runs away from an orphanage. Wandering through the Tokyo slums, he meets former boxing trainer Danpei. Joe is later arrested and goes to a temporary jail where he fights Nishi, his future best friend, ​and leader of a group of hooligans. He and Nishi then go to a juvenile prison miles away from Tokyo. There Joe meets Rikiishi, a former boxing prodigy, and a rivalry develops between them. They face each other in a match in which Rikiishi dominates Joe until the latter hits him with a cross-counter, resulting in both being knocked out. This inspires the other prison inmates to take up boxing. Joe and Rikiishi vow to fight again. 
(Source: Wikipedia)

Joe, a teenage orphan in the slums of the Doya streets, meets Danpei, a homeless, alcoholic ex-boxing coach. Danpei, seeing Joe's boxing talent, decides to train him. When Joe is sent to a terrible juvenile home for petty crimes, he meets Rikiishi who becomes his boxing rival. Danpei arrives at the home to help Joe to train in order to defeat Rikiishi. When Joe decides to seriously pursue boxing, Danpei cannot get a coaching license because of his reputation as a drunk. 
(Source: AnimeNfo)

Asou Mitsuko is a retired voice actress from Tokyo, Japan. She was active between 1950 and 1972.

Pilot films for Ashita no Joe, released as bonus material on the series' DVD box. 
 
- Aoyama-hen (prod. 1969/11/06) 
- Rikiishi-hen (prod. 1969/12/22)