Ippo Makunouchi, the protagonist of the anime/manga series Hajime no Ippo (also known as Fighting Spirit)
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A shy young man, yet a very bold boxer, Ippo is trained by Genji Kamogawa. He is good with techniques such as his comeback KO victories, his Peek-a-Boo style defense, and the Dempsey roll.
vs.
Ryuuji Takane, the protagonist of the anime/manga series Ring ni Kakero (or Put It All in the Ring)
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Ryuuji is a fierce and spirited young man who is trained in boxing techniques by his older sister Kiku. He has strong skill in basic techniques like jabs and one-twos. His special attacks include the Boomerang Hook and Boomerang Telios.
Who would in a boxing match between these two spirited fighters?
Ippo already hits well beyond his weight class, and that seems to be one or two above Ryuuji. Also Ippo is damn fast and knows how to really scrap. I've never seen Ring ni Kakero, but based on all of Ippo's fights and accomplishments, I'd give him the majority win.