Image © Shōga Kensha

The Kai Ken is a member of the medium sized Nihon Ken originating from the Yamanashi Prefecture, originally known as the Kai Province. They were recognised as a natural monument in 1933, and are considered a rare breed even in Japan.

Kai were originally used in hunting, with the breed having two types:
shishi-inu-gata, a bear faced dog used for hunting boar, featuring a stockier and heavier built dog.
shika-inu-gata, a fox faced dog used for hunting deer. The deer type has a thinner, lighter build with a longer body.

However, there is no longer a distinction made between the two types, and neither type is preferred by the Kai Ken Aigokai. While the Kai is primarily seen as a pet now, they are occasionally still used in hunting.

Of the medium sized dogs, the Kai lands on the small end of the spectrum, between the Shiba, the small sized Nihon Ken, and the Hokkaido, Kishu and Shikoku.

Kai are double coated and come in three coat colours: aka-tora (red brindle), chu-tora (medium brindle) and kuro-tora (black brindle). There is also a recessive gene for cream coloured Kai, though this colour is not recognised and is non-standard, as the cream colouring takes away from the Kai’s natural camouflage. They also often have black spots covering their tongues. Their tails can be curled (maki-o) or sickle (sashi-o).

Kai are an intelligent breed, often described as independent thinkers. They are naturally aloof with strangers and unknown dogs, but should not be overly shy or aggressive. They can be more flighty when spooked than the other Nihon Ken breeds, but become very attached to their owner and family. They are quick learners and are willing to please their owners if the owner puts in the effort to work with their Kai.

Image © Shōga Kensha

FCI Breed Standard

Standard for FCI

UTILISATION: Hunting dog, companion.

FCI-CLASSIFICATION: Group 5 Spitz and primitive type. Section 5 Asian Spitz and related breeds.

General Appearance:

Medium-sized dog, well balanced, sturdily built, muscles well developed. The dog has the characteristics of a dog living in mountainous districts of Japan. Limbs strong and hocks remarkably developed.

Important Proportions:

The ratio of height at withers to length of body is 10:11, but the body can be slightly longer in bitches.

Behaviour / Temperament:

The temperament is keen and very alert.


Skull: Forehead broad.
Stop: Abrupt with slight furrow.

Nose: Black, nasal bridge straight.
Muzzle: Pointed, not very long, but moderately thick.
Lips: Tight.
Jaws/Teeth: Strong with a scissor bite.
Cheeks: Well developed.
Eyes: Nearly triangular and dark brown in colour. The outer corners of the eyes are slightly upturned.
Ears: Triangular, slightly inclining forward and firmly pricked.


Thick, powerful and muscular.


Withers: High.
Back: Straight and short.
Loin: Broad and muscular.
Chest: Deep, ribs moderately sprung.
Belly: Slightly tucked up.


Set on high, thick, vigorously curled or carried curved like a sickle over the back. Tip nearly reaching the hocks when let down.


Shoulders: Moderately sloping with developed muscles.
Upper arm: Forming a moderate angle with shoulder blade.
Elbows: Close to the body.
Forearm: Straight, heavy and muscular.
Metacarpus (Pastern): Slightly oblique.
Forefeet: Toes well arched and tightly knit; pads thick and elastic; nails hard and preferably dark in colour.

General appearance: Well developed, strong and moderately angulated.
Hocks: Tough and elastic.
Hind feet: Toes well arched and tightly knit; pads thick and elastic; nails hard and preferably dark in colour.

Gait / Movement:

Light and resilient.


Hair: Outer coat harsh and straight; undercoat soft and dense. The hair on the tail is fairly long and off-standing.

Colour: Black brindle, red brindle and brindle. As a feature of this breed, solid colour in puppyhood may turn brindle as the dog grows.


Height at withers: Males 50 cm. Females 45 cm. There is a tolerance of + 3 cm.


Any departure from the foregoing points should be considered a fault and the seriousness with which the fault should be regarded should be in exact proportion to its degree and its effect upon the health and welfare of the dog.

  • Lack of sexual dimorphism.
  • Light-coloured nose.
  • Slightly overshot or undershot mouth.
  • Light-coloured eyes.
  • Long or short hair.
  • Shyness.

Disqualifying Faults:

  • Aggressive or overly shy.
  • Any dog clearly showing physical or behavioural abnormalities
    shall be disqualified.
  • Extremely overshot or undershot mouth.
  • Ears not pricked.
  • Hanging tail, short tail.
  • Faded colour.
  • Coat with many white spots.
  • Pinto colour.
  • Male animals should have two apparently normal testicles fully descended into the scrotum.
  • Only functionally and clinically healthy dogs, with breed typical conformation, should be used for breeding.

NIPPO Breed Standard

The NIPPO standard for the Kai Ken is outlined in a single standard for all four of the medium sized Nihon Ken. An excellent translation of the NIPPO standard can be viewed here by E. Ishii.

Image © Fédération Cynologique Internationale

KKA Breed Standard

Kindly translated by Shigeru Kato

Substance and Appearance:

Showing proper sexual dimorphism, and an unadorned unsophisticated air coupled with composed boldness. Movement light and nimble, the breed is agile and powerful with strong homing instinct and a propensity toward loyalty to one master for life.

The outer coat standing upright, undercoat thick, and animals should have a mane.

The breed is split into three coat colors, black brindle, medium brindle, and red brindle.

There are two body types, boar type, and deer type.

Height roughly 40-50 centimeters at withers.


Moderately thick, triangular in form, of good shape and angled forward, spacing between ears neither too wide apart or close together, lines clean and without looseness, and ears slightly larger than the other Japanese dog breeds.


More or less triangular in shape, the iris dark brown, which depending on coat color may show some shading.


Lips tight, with good pigmentation, teeth strong, proper bite.

Head & Neck:

Forehead wide falling to a moderate stop, neck having appropriate thickness and length, without looseness.

Back & Hips:

Line of the back straight, hips powerful and tight.


Tail thick and strong, either sickle tail or curl tail type, roughly reaching the hocks in length.


Robust with hocks especially well developed, firm while providing for excellent leaping ability and speed.

Kai Ken in Media

Many Kai play key roles within Yoshihiro Takahashi’s series, particularly Ginga: Nagareboshi Gin and Ginga Densetsu Weed.

Image © Yoshihiro Takahashi

In Capcom’s 2006 game ‘Okami’, Hayabusa/Chu, a canine warrior, is a Kai Ken.

Image © Capcom