# Kai Ken (甲斐犬)

Nihon Ken — Kai Ken. Breed health: 1,752 dogs, 325 founders, gene diversity 98.83%.

See all Kai Ken: https://nihonken.org/pedigree/browse?breed=kai&format=md

## Overview
A free population-genetics overview across the 1,752 Kai Ken in the database — gene diversity, inbreeding over time, and the ancestors shaping the lines. Every figure is a floor on incomplete pedigrees: true values may be higher.

## Genetic diversity
- **Dogs:** 1,752
- **Founders:** 325
- **Gene diversity:** 98.83%
- **Mean kinship:** 1.17% · sampled estimate
- **Effective population (Ne):** Not estimable — Mean inbreeding is not rising in the data (ΔF ≤ 0), so Ne is not estimable. Pedigree-based estimate from the rate of inbreeding, not a census Ne; a floor given incomplete pedigrees.

## Inbreeding over time
Mean cached COI per birth-year cohort (1,085 dogs with a computed COI). Population means, not individual COIs.

1933 — 6.25% (1 dogs)
1948 — 0.00% (1 dogs)
1956 — 1.56% (1 dogs)
1961 — 8.18% (1 dogs)
1963 — 8.20% (1 dogs)
1964 — 20.63% (1 dogs)
1965 — 20.31% (1 dogs)
1966 — 30.00% (2 dogs)
1967 — 16.73% (7 dogs)
1968 — 28.22% (1 dogs)
1969 — 11.20% (7 dogs)
1970 — 3.06% (4 dogs)
1971 — 1.09% (2 dogs)
1972 — 27.96% (1 dogs)
1973 — 14.55% (2 dogs)
1986 — 1.22% (1 dogs)
1989 — 14.99% (1 dogs)
1991 — 0.00% (5 dogs)
1993 — 0.00% (6 dogs)
1994 — 0.00% (5 dogs)
1995 — 8.78% (5 dogs)
1996 — 0.00% (2 dogs)
1997 — 6.33% (3 dogs)
1998 — 13.59% (3 dogs)
1999 — 6.28% (5 dogs)
2000 — 0.00% (4 dogs)
2001 — 4.22% (5 dogs)
2002 — 0.00% (1 dogs)
2003 — 10.56% (8 dogs)
2004 — 9.95% (8 dogs)
2005 — 0.00% (3 dogs)
2006 — 2.47% (9 dogs)
2007 — 9.66% (22 dogs)
2008 — 10.06% (21 dogs)
2009 — 7.74% (17 dogs)
2010 — 5.60% (28 dogs)
2011 — 9.63% (51 dogs)
2012 — 1.56% (52 dogs)
2013 — 2.38% (39 dogs)
2014 — 3.28% (44 dogs)
2015 — 3.83% (48 dogs)
2016 — 3.84% (47 dogs)
2017 — 5.06% (34 dogs)
2018 — 3.66% (74 dogs)
2019 — 2.43% (46 dogs)
2020 — 2.70% (73 dogs)
2021 — 4.09% (32 dogs)
2022 — 3.49% (41 dogs)
2023 — 3.41% (48 dogs)
2024 — 2.91% (25 dogs)
2025 — 3.85% (24 dogs)

## Most influential dogs
Effective number of ancestors: 27.8. The modern Kai Ken gene pool is as concentrated as if 27.8 equally used dogs had produced it. Ranked by each dog's own contribution to the 713 Kai Ken born since 2011 with a recorded pedigree (as of 2026-10-11): the part of the modern gene pool that passes through that dog and through no dog ranked above it. The top 20 account for 70.5% of it. A dog's reach, the share of pedigrees it appears in, is a minimum: a pedigree that stops early can hide descent, never invent it. Own contributions and the effective number of ancestors are estimates from the recorded pedigrees, and can move either way as more ancestry is recorded.
- **#1:** [Kai Kokushin go Jōnan Kensha (2000) · own contribution 8.9% · in 74.1% of pedigrees](https://nihonken.org/pedigree/dogs/57f254ec-082f-43b1-9bfb-b212a7b13e2f)
- **#2:** [Aya no Takahime go Funato Kamiyama-sō · own contribution 8.3% · in 78.8% of pedigrees](https://nihonken.org/pedigree/dogs/0f2b9dc4-c306-4193-aafc-494cfb5dda69)
- **#3:** [Wakahonjin go Fujimine (2004) · own contribution 6.3% · in 54.7% of pedigrees](https://nihonken.org/pedigree/dogs/0de0b306-50a4-4ba6-ba70-010b7de9dede)
- **#4:** [Walnut Valley's Mavis O'MM (1993) · own contribution 4.6% · in 40.7% of pedigrees](https://nihonken.org/pedigree/dogs/d55cc1e0-0898-4323-ad84-1634abf61d3b)
- **#5:** [Kaihime Go Ichiwa Kensha · own contribution 3.9% · in 52.7% of pedigrees](https://nihonken.org/pedigree/dogs/d9cace8c-0bc2-444f-bef3-54e9828c9f33)
- **#6:** [Tone no Sakurahime go Saitō Kensha · own contribution 3.7% · in 53.9% of pedigrees](https://nihonken.org/pedigree/dogs/8c96f269-d6c0-4d84-a657-66d08b6d13d2)
- **#7:** [Rikirō go Takahata Kensha (1986) · own contribution 3.2% · in 40.7% of pedigrees](https://nihonken.org/pedigree/dogs/16787fce-0994-4086-b00f-6a784049715c)
- **#8:** [Hakuhou No Ryuu Go Kawasaki Kobayashi Kensha · own contribution 3.1% · in 57.6% of pedigrees](https://nihonken.org/pedigree/dogs/cab86899-0c71-41f3-8a08-4c8ae4c7e398)
- **#9:** [Tetsuryū go Ichikawa Tanaka Kensha · own contribution 3% · in 52.5% of pedigrees](https://nihonken.org/pedigree/dogs/b671d8e4-c2d3-48c7-afae-0e53c243a984)
- **#10:** [Kibi Shinkou Go Kairou Kensha · own contribution 2.9% · in 28.2% of pedigrees](https://nihonken.org/pedigree/dogs/2ca89a4c-f182-497c-9716-3f121fc84257)
- **#11:** [Gen Go Yugiri Sou (2010) · own contribution 2.8% · in 14.3% of pedigrees](https://nihonken.org/pedigree/dogs/5196c263-daec-436f-aa63-4a0c1d12c066)
- **#12:** [Minimeadow Kilo (1995) · own contribution 2.7% · in 40.4% of pedigrees](https://nihonken.org/pedigree/dogs/cb39d021-e2cf-41f3-ae75-0c32f6475366)
- **#13:** [Sagami Kaihime Go Kouyou Kensha (2004) · own contribution 2.7% · in 22.7% of pedigrees](https://nihonken.org/pedigree/dogs/ca709e74-6ed3-48a5-8656-ca476bcbfb26)
- **#14:** [Nanyou No Rikiou Go Nanyou Satou Kensha (2006) · own contribution 2.7% · in 25.7% of pedigrees](https://nihonken.org/pedigree/dogs/70e3fd83-d963-42ad-88a3-a556ed89775d)
- **#15:** [Kairou Go Jounan Kensha · own contribution 2.6% · in 43.6% of pedigrees](https://nihonken.org/pedigree/dogs/d59cf88f-d0ce-457a-909c-27e4b049f871)
- **#16:** [Minimeadow Kiku Ishiwa Maruyoshi (1991) · own contribution 2% · in 40.7% of pedigrees](https://nihonken.org/pedigree/dogs/968b2775-6b29-42d1-aa7a-1bd2ed30d66b)
- **#17:** [Shinkou Go Kai Ryuosow · own contribution 1.9% · in 8.4% of pedigrees](https://nihonken.org/pedigree/dogs/a62190e5-1b9f-4e0f-8d16-5bd33e55f4e0)
- **#18:** [Kishin Go Rokka Sou (1999) · own contribution 1.8% · in 30.6% of pedigrees](https://nihonken.org/pedigree/dogs/99364583-3a29-4d3c-89fc-94b0585e7f3b)
- **#19:** [Mitake no Tora Go Mitake Rou Kensha · own contribution 1.7% · in 21.2% of pedigrees](https://nihonken.org/pedigree/dogs/5c5dfb58-8073-4068-b75f-6f3c75fe891a)
- **#20:** [Tenrou no Tsubakihime go Tenrou Kensha (2008) · own contribution 1.6% · in 20.3% of pedigrees](https://nihonken.org/pedigree/dogs/8c94905d-53c7-4e44-8a21-056beb3d9f42)

## Dogs
- **Chitan go Miyamoto-sō Adachi-shi チタン号 宮本荘 足立氏:** [](https://nihonken.org/pedigree/dogs/c5831fdb-59b1-4a46-8329-bbc910719d0e)
- **Kai go Kobayashi-shi ⼩ 甲斐号 林氏:** [](https://nihonken.org/pedigree/dogs/2921f48f-86f9-4241-8a62-3d75890d754b)
- **Ken go (Ken go ) Nishiyama-sō Kobayashi-shi ⼩ 剣号 ケン号 西山荘 林氏:** [](https://nihonken.org/pedigree/dogs/6f87f00d-247b-4364-b840-59d9c35aa3c5)
- **Kikumi Go Fuurinkazan:** [](https://nihonken.org/pedigree/dogs/292ebbe7-ac76-415a-86f1-86e850db198a)
- **Tatsu go 竜号:** [](https://nihonken.org/pedigree/dogs/e2e9ea23-e3b6-4688-9749-9c91c07c9b28)
- **A'Karube Go des Fidèles Akita Ken:** [LOF 79](https://nihonken.org/pedigree/dogs/68d71a93-3492-4c55-ad04-4a0114926dad)
- **A'Kohime Go des Fideles Akita Ken:** [LOF 83](https://nihonken.org/pedigree/dogs/e3c9ca9c-aefd-47a3-a045-9efab094a195)
- **A'Kurai Go des Fidèles Akita Ken:** [LOF 84](https://nihonken.org/pedigree/dogs/44c91333-fe46-4c8c-bcc2-f5c1c5083d38)
- **Akahana Go Ounoki Kensha 赤花号 王の木犬舎:** [](https://nihonken.org/pedigree/dogs/47b7b03c-8503-449e-90c7-dd8beb90bd1e)
- **Akaryuu Go Ounoki Kensha 赤竜号 王の木犬舎:** [](https://nihonken.org/pedigree/dogs/c5efdf28-07cd-4109-9a5b-f965f4fca8d7)
- **Akira Kenmaru go GO Proud FCI 明拳丸号 誇り号:** [](https://nihonken.org/pedigree/dogs/adcf2baf-d40e-492d-a352-9b98cc695634)
- **Aoarashi no Roushin go Yuugiri Sou 青嵐乃狼神号 夕霧荘:** [KKA 47664](https://nihonken.org/pedigree/dogs/7bd4fba9-855a-4f59-863e-3441a21c9a20)
- **Besmira's Princess Aurora Borealis:** [](https://nihonken.org/pedigree/dogs/9498d292-104e-4625-a341-92d6792f4109)
- **Besmiras Kai Jr. Like His Father:** [](https://nihonken.org/pedigree/dogs/b5d2f337-dbb8-4883-8dc7-faf2b4b75bac)
- **Bi No Jouou Go Ihoku Hakurensou 伊北白蓮荘:** [](https://nihonken.org/pedigree/dogs/b8c1c958-184c-4337-af11-ef8b088b94f6)
- **Classy's Arctic Moonlight:** [](https://nihonken.org/pedigree/dogs/a26cac33-51d0-44a4-8fd6-9343e2f047dd)
- **Classy's Hello Kitty Go Lightly:** [AKC WS48576501](https://nihonken.org/pedigree/dogs/304b9411-518b-462d-af20-5482040de531)
- **Dairō go Saga Shio Kensha (Hayashi Tokiharu-shi ) 大狼号 嵯峨塩犬舎 林時春氏:** [KKA 4298](https://nihonken.org/pedigree/dogs/d68aa305-9aca-4fc7-97ed-7ddea65300e5)
- **En go Morisawa-shi エン号 森沢氏:** [KKA 43](https://nihonken.org/pedigree/dogs/da64abd9-0d51-48ca-9894-9f0f12d6679d)
- **Fujihime go Chitoseya-sō 富士姫号 千歳屋荘:** [KKA 2160](https://nihonken.org/pedigree/dogs/cb41f764-b014-4172-b0ba-f3b402108736)
- **Gekkoo No Amaya:** [](https://nihonken.org/pedigree/dogs/a81c9e6e-60c0-4350-a4db-814441e5b54e)
- **Gekkoo No Daranibo:** [](https://nihonken.org/pedigree/dogs/c67818fc-7c02-4068-b92a-501fe3e74f12)
- **Gekkoo No Etsuko:** [](https://nihonken.org/pedigree/dogs/00fa8fea-3bc4-411f-b75a-65eb61a13b12)
- **Gekkoo No Saanan Salaisuus:** [](https://nihonken.org/pedigree/dogs/ab967812-6ac0-4e8d-ac50-49a864c28815)

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