Bakudan 

The story follows Baku Ryosuke, also known as "Bakudan" a fresh-out-of-juvy punk and a dangerous street-fighter who is scouted by a yakuza syndicate and dreams of becoming the greatest yakuza in Japan. However, to teach Bakudan a lesson, the yakuza send him to the gym of a retired heavyweight boxer named Ken Tamaki to get him to sign away his property. But after fighting Bakudan for the property, Tamaki becomes impressed by Bakudan’s fighting skills, and from then on devotes himself to helping Bakudan follow his true destiny… to become the first heavyweight world champion boxer from Japan!