At a glance the quick version
No weight in the FCI standard; UKC gives 25-55 lb for the breed and Wikipedia 11-25 kg, not split by sex.
FCI: dogs 50 cm and bitches 45 cm, each plus or minus 3 cm. UKC: 18.5-22 in and 17.5-20 in. Wikipedia: 50-56 cm and 45-51 cm.
Coat and looks how to spot one
medium-length double coat
A sturdy, well-muscled mountain dog of medium size with strong legs and pricked ears. A harsh, straight outer coat sits over a soft, dense undercoat, and the tail hair is fairly long and stands out.13
Personality what they are like
Keen, alert and brave, with a real attachment to its own people. It tends to be reserved with strangers but friendly once it knows someone, and it usually gets along with other dogs.132
Daily activity how busy a day looks
High. Bred to hunt in steep country, it enjoys long walks, hikes and chances to explore and climb.123
Grooming and care the hands-on bits
Brush the double coat regularly, more often while the undercoat sheds.13
Home where they are happiest
Suits an active home with secure outdoor space; it is an agile climber, so fences need to be sound.2
Company who they like around
Bonds closely with its household and makes a good watchdog; it does best living as part of the family.32
The story where it all began
The Kai comes from medium-sized dogs of ancient Japan that settled into the isolated mountains of the Kai district, where hunters used them for deer and wild boar. A preservation society, the Kai Ken Aigokai, was set up in 1931, and the breed was named a natural monument soon after (1933 per Wikipedia, 1934 per the FCI and UKC).132
Fun facts for the dinner table
- 1
Puppies are born a solid colour and their brindle stripes can take up to five years to fully show.2
- 2
Kai have been known to swim across rivers and even climb trees while following game.2
- 3
Its striped coat earned it the nickname 'Tora', meaning tiger.3
- 4
The AKC notes it is considered rare even in Japan.4
Recognised by the official bits
- FCI
- Standard no. 317 as 'Kai', Group 5 Spitz and primitive type, Section 5 Asian Spitz and related breeds; official valid standard published 30.10.2016.1
- Japan Kennel Club
- Recognised breed.2
- UKC
- Recognised 1 January 1997 as 'Kai', Northern Breed Group.3
- AKC
- Listed by the AKC as one of the six native Japanese breeds (Nihon Ken).4
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Kai Ken. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- BrushingDaily during heavy sheddingevery 3 days
- Double coats insulate against cold and heat, so shaving is not recommended
- Bathevery 10 weeks
- Nail trimSooner if you hear clicking on the floorevery month
- Ear checkevery 2 weeks
- Teeth brushingDaily brushing is idealevery 2 days
- ExerciseDaily walks and playevery day
- Flea, tick and worm protectionSchedule as your vet recommendsas your vet recommends
- Vet check-upSenior years usually start around age 8every year
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FCI standard no. 317, Kai fci.beused for recognition, size, coat, colours, temperament, history
- Kai Ken, Wikipedia en.wikipedia.orgused for other names, brindle names, preservation history, fun facts
- UKC Kai breed standard ukcdogs.comused for recognition, size, weight, temperament, nickname
- AKC Kai Ken breed page akc.orgused for Nihon Ken status, rarity, intelligence
Checked 2026-09-30. Text is written in our own words from these sources.