Shiroi Senshi Yamato

Yamato the White Warrior (白い戦士ヤマト, Shiroi Senshi Yamato) is a manga written and illustrated by Yoshihiro Takahashi.

Plot
Shiroi Senshi Yamato is about a white Akita pup who strives to become the champion fighting dog of Yamagata. Over the course of the series, the main villain - Toshio - hires multiple people to attempt to kill Yamato and stop him being champion, which results in many adventures besides the fights themselves.