Hachi is the pet dog of Nekota Ginpachi. He is possibly a mix between an Akita and an Alaskan Malamute (according to Morikawa himself). He made his appearances in Tokyo with Nekota when watching the matches of the Kamogawa boxers. But Nekota could not enter Hachi because pets are not allowed in Kourakuen Hall. So, in Nekota's next return to Tokyo, he hid Hachi in a large sack.
Hachi is the father of Wanpo (Ippo's dog) which Nekota gave to Ippo as a gift.