The Tosa Inu breed is the result of crossbreeding which took place between 1868 and 1912 by crossing Kochies, Bull Terriers, Bulldogs, Great Danes, and Saint Bernards. The name comes from the land where this breed was raised, and its proud, combative, and lively temperament comes from the crossbreeding that led to this final result. In the Japanese province of Kochi, a breed of dog was raised exclusively for fighting, but during the Meiji period, between 1868 and 1912, they began crossing the local breed with various European ones such as “Bulldogs”, “Bull Terriers”, “Mastiffs”, “Saint Bernards” and “Great Danes”; thus a new breed was created with greater fighting skills, that was tougher and more resistant, a more or less unbeatable fighting dog.

This new breed is known today by the names of Tosa-Inu (Tosa Dog), Tosa-Ken or Tosa-Token. Its land of origin is the Island of Shikoku in the Kochi prefecture, where the city of Tosa is situated, which the breed is named after.

Japan has a long tradition of fighting dogs that dates back to the XIV century.

Bearing the name of the region where it was raised, the Tosa Inu is sometimes called “Japanese dog” or “Japanese fighting dog”.

The western dogs that were employed in the creation of this breed were the following: Bulldogs (1872), Mastiffs (1874), Bull Terriers, German Pointers (1876), and Deutsche Dogges or Great Danes (1924).