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Tosa Inu
Characteristics, History, and Health

Tosa Inu

The Tosa Inu, also known as Tosa Ken, Tosa Dog, or Japanese Mastiff, hails from Japan, where it was bred as a fighting dog. It originated in the second half of the 19th century in Tosa (present-day Kochi), which is how the breed got its name. The breed was created by crossing local Japanese dogs with several foreign breeds like the English Bulldog, Mastiff, Saint Bernard, and the German Pointer, to create a powerful and agile fighting dog. The resulting breed was not only a capable fighter but also highly intelligent and trainable.

Main Info
Alternate Names
Tosa, Tosa Dog, Tosa-Ken, Tosa Tōken, Japanese Mastiff
Life Expectancy
10-12 years
Average Male Height
Minimum 21.5-23.5 inches
Average Female Height
Minimum 21.5-23.5 inches
Average Male Weight
100-200 pounds
Average Female Weight
100-200 pounds
Coat Length
Coat Type
Smooth, Double
Coat Colors
Red, Fawn, Black, Brindle
Coat Pattern
White Markings

Genetic Predispositions and Health

Like other large breeds, Tosa Inus can be predisposed to a few health conditions. Some of the common health issues seen in this breed include hip and elbow dysplasia, heart disease, allergies, and gastric torsion (also known as bloat).

Personality and Behavior

Tosa Inus are known for their quiet, patient, and calm temperament. They are brave and confident, with a natural protective instinct, making them excellent watchdogs. Despite their history as fighting dogs, they can be very gentle and affectionate towards their human families. However, due to their size and strength, they are not recommended for novice dog owners. Proper socialization and training from a young age is essential.

Fun Facts

In their native Japan, Tosa Inus are often referred to as the "Sumo wrestler of the dog world" because of their size and their history in dog fighting, which was conducted in a manner similar to sumo wrestling.

Despite their fearsome reputation and size, Tosa Inus are known to be 'silent' fighters, and they are often called the "Silent Tosa" as they do not typically bark or growl while fighting.

Tosa Inus are a rare breed, even in Japan, and owning one can be considered a status symbol.