Jungle Taitei: Susume Leo!  

New Jungle Emperor, Go Ahead Leo!, Onward Leo!, ジャングル大帝・進めレオ

The Jungle Emperor was a popular show in Japan that led to the production of a sequel called "The New Jungle Emperor" or "Onward, Leo!" However, Dr. Tezuka made this series without a deal with NBC, which resulted in it being more similar to his original manga story and featuring some depressing episodes. This caused problems for NBC as they were unable to sell the show, but they did manage to produce 52 episodes before deciding not to air the New Jungle Emperor series outside of Japan until 1984 when it was given the title Leo The Lion. The new series took place a few years after the original Kimba series and focused on Rune, the male cub as he grew and learned to be strong like his father. Due to legal reasons, the producers of the English-dubbed version were unable to use the name Kimba and instead used the original Japanese names for all characters in the show.