A study of the 1930s carried out by the Japanese cynologist Haruo Isogai classified all native Japanese dog breeds into three categories: large-, medium-, and small-sized. The Shikoku belongs to the Shika-inus, the medium-sized dogs. Other medium-sized dogs are the Kai Ken, the Ainu and the Kishu Inu. They are all very similar with overlapping colors and only minor differences in size and morphology.
Shikoku dogs are tough and sufficiently agile to run through a mountainous region. They are the ideal companion for active outdoor people. They are very energetic and active outside but they are calm and quiet indoors. The Shikoku is a very intelligent dog and a quick learner. They are not as stubborn and independent as the other native Japanese breeds, but still it is not a dog for every person. The Shikoku stands 17-21 inches (43-53cm) high and comes in sesame (white, red, black) or solid red. The body confirmation is typically of the spitz-type: the square body, the wedge-shaped head, the prick triangular ears, and feathered curled tail.
The Shikoku dog is somewhat unique in its appearance. It looks similar to an Alaskan Husky dog physically, but differs in its size and color. The Shikoku Inu, when healthy, ranges from thirty-five to fifty-five pounds (male) and from seventeen to twenty-one pounds (female). This dog would be considered medium sized. The Shikoku Inu can be seen in a variety of colors, sometimes even mixed ones. These colors consist usually of a light brown, a light red-brown, or a light black-brown. In addition, there is a cream colored coat that tends to be very rare. In all of these colors there is usually a mixture of white found around the underside of the body, near the eyes, snout, and legs. The Shikoku tends to shed its coat at least one to two times a year. The dog has a fairly thick coat with pointed ears and a curved tail. Since this breed is so rare, any of the variety of color combinations would be considered a prize.
The savage Koga Dogs of the Japanese manga series Ginga: Nagareboshi Gin are thought to be Shikoku, although they are portrayed as having mohawk-like shocks of fur on their heads. Kurojaki is the scythe-wielding leader of these dogs, and his son Tesshin is an important hero in the sequel series Ginga Legend Weed. Both series are by Yoshihiro Takahashi.