This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. If an article link referred you here, you might want to go back and fix it to point directly to the intended page.
The large height and weight ranges in the Tosa breed is due to their background in dog fighting; they are grouped into light, middle and heavyweight classes.
It was developed between the period of 1868 and 1912 by crosses with the Kochi (a local Japanese breed) and native Shikoku fighting dogs.
The Tosa is a rare breed, even in their native land and have only recently been introduced to the USA.