# Shikoku Ken breed report 2026 Population-genetics report for Shikoku Ken, 2026: 4,169 dogs on file, 1,165 born in the last 8 years. ## Summary - **Dogs on file:** 4,169 - **Born in the last 8 years:** 1,165 - **Reference sample:** 500 dogs (seed 2026, 10 generations) - **Computed:** 2026-09-04 ## Inbreeding over time Mean cached COI per birth-year cohort — population means, not individual COIs. Every figure is a floor: COI is capped at a fixed generation depth, so the true mean may be higher. 1948 — ≥ 23.24% (Elevated) · 1.5% complete · 2 dogs 1949 — ≥ 2.34% (Indicative) · 1.4% complete · 1 dogs 1950 — ≥ 2.34% (Indicative) · 1.5% complete · 1 dogs 1951 — ≥ 30.27% (Elevated) · 2.6% complete · 1 dogs 1952 — ≥ 5.57% (Indicative) · 1.7% complete · 2 dogs 1953 — ≥ 16.01% (Elevated) · 1.6% complete · 2 dogs 1954 — ≥ 21.42% (Elevated) · 2.7% complete · 4 dogs 1955 — ≥ 11.67% (Moderate) · 3.5% complete · 2 dogs 1956 — ≥ 6.97% (Moderate) · 6% complete · 3 dogs 1957 — ≥ 18.63% (Elevated) · 4.1% complete · 3 dogs 1958 — ≥ 9.67% (Moderate) · 6.5% complete · 10 dogs 1959 — ≥ 13.44% (Elevated) · 8% complete · 12 dogs 1960 — ≥ 10.38% (Moderate) · 10.1% complete · 6 dogs 1961 — ≥ 16.83% (Elevated) · 11.8% complete · 13 dogs 1962 — ≥ 19.04% (Elevated) · 17.3% complete · 6 dogs 1963 — ≥ 19.94% (Elevated) · 18.6% complete · 9 dogs 1964 — ≥ 19.87% (Elevated) · 20.6% complete · 6 dogs 1965 — ≥ 14.27% (Elevated) · 23.1% complete · 11 dogs 1966 — ≥ 11.72% (Moderate) · 25.3% complete · 4 dogs 1967 — ≥ 16.37% (Elevated) · 36.3% complete · 7 dogs 1968 — ≥ 11.75% (Moderate) · 38.6% complete · 11 dogs 1969 — ≥ 13.96% (Elevated) · 35.4% complete · 6 dogs 1970 — ≥ 13.18% (Elevated) · 50.3% complete · 3 dogs 1971 — ≥ 24.85% (Elevated) · 31.5% complete · 4 dogs 1972 — ≥ 19.3% (Elevated) · 67.4% complete · 5 dogs 1973 — ≥ 17.39% (Elevated) · 59.9% complete · 7 dogs 1974 — ≥ 9.26% (Moderate) · 50.2% complete · 2 dogs 1975 — ≥ 7.94% (Moderate) · 59.6% complete · 3 dogs 1976 — ≥ 16.01% (Elevated) · 61.1% complete · 6 dogs 1977 — ≥ 9.37% (Moderate) · 59.7% complete · 5 dogs 1978 — ≥ 14.25% (Elevated) · 57.7% complete · 9 dogs 1979 — ≥ 16.7% (Elevated) · 48.8% complete · 7 dogs 1980 — ≥ 13.44% (Elevated) · 62.1% complete · 10 dogs 1981 — ≥ 16.34% (Elevated) · 64.6% complete · 10 dogs 1982 — ≥ 12.17% (Moderate) · 63.1% complete · 14 dogs 1983 — ≥ 14.11% (Elevated) · 58.4% complete · 15 dogs 1984 — ≥ 7.63% (Moderate) · 50.3% complete · 5 dogs 1985 — ≥ 10.84% (Moderate) · 51.1% complete · 16 dogs 1986 — ≥ 11.77% (Moderate) · 53.3% complete · 10 dogs 1987 — ≥ 9.6% (Moderate) · 52.6% complete · 25 dogs 1988 — ≥ 11.71% (Moderate) · 59.8% complete · 14 dogs 1989 — ≥ 9.14% (Moderate) · 57.3% complete · 14 dogs 1990 — ≥ 11.35% (Moderate) · 53.2% complete · 16 dogs 1991 — ≥ 14.83% (Elevated) · 68.5% complete · 10 dogs 1992 — ≥ 13.1% (Elevated) · 66.9% complete · 10 dogs 1993 — ≥ 9.61% (Moderate) · 59.4% complete · 15 dogs 1994 — ≥ 12.69% (Elevated) · 75.8% complete · 9 dogs 1995 — ≥ 13.92% (Elevated) · 73.4% complete · 9 dogs 1996 — ≥ 10.72% (Moderate) · 64.7% complete · 12 dogs 1997 — ≥ 8.1% (Moderate) · 62.6% complete · 4 dogs 1998 — ≥ 18.58% (Elevated) · 81.9% complete · 6 dogs 1999 — ≥ 12.3% (Moderate) · 80% complete · 6 dogs 2000 — ≥ 11.43% (Moderate) · 81.4% complete · 8 dogs 2001 — ≥ 12.88% (Elevated) · 88.9% complete · 10 dogs 2002 — ≥ 4.29% (Indicative) · 55.3% complete · 1 dogs 2003 — ≥ 17.11% (Elevated) · 87.8% complete · 6 dogs 2004 — ≥ 16.38% (Elevated) · 87.6% complete · 3 dogs 2005 — ≥ 11.53% (Moderate) · 86.1% complete · 16 dogs 2006 — ≥ 12.8% (Elevated) · 89.4% complete · 23 dogs 2007 — ≥ 12.87% (Elevated) · 90.2% complete · 19 dogs 2008 — ≥ 14.23% (Elevated) · 93.4% complete · 17 dogs 2009 — ≥ 12.93% (Elevated) · 86.8% complete · 23 dogs 2010 — ≥ 12.75% (Elevated) · 90.4% complete · 43 dogs 2011 — ≥ 14.5% (Elevated) · 92.8% complete · 37 dogs 2012 — ≥ 13.58% (Elevated) · 93.8% complete · 50 dogs 2013 — ≥ 13.52% (Elevated) · 93.5% complete · 58 dogs 2014 — ≥ 11.25% (Moderate) · 93.4% complete · 86 dogs 2015 — ≥ 12.35% (Moderate) · 93.8% complete · 89 dogs 2016 — ≥ 13.02% (Elevated) · 92.8% complete · 138 dogs 2017 — ≥ 12.47% (Moderate) · 94.9% complete · 111 dogs 2018 — ≥ 12.44% (Moderate) · 96.3% complete · 148 dogs 2019 — ≥ 11.65% (Moderate) · 96.2% complete · 158 dogs 2020 — ≥ 9.25% (Moderate) · 95.6% complete · 169 dogs 2021 — ≥ 11.03% (Moderate) · 96% complete · 205 dogs 2022 — ≥ 9.43% (Moderate) · 96.7% complete · 119 dogs 2023 — ≥ 11.21% (Moderate) · 96.7% complete · 109 dogs 2024 — ≥ 9.95% (Moderate) · 97.5% complete · 124 dogs 2025 — ≥ 9.65% (Moderate) · 97.2% complete · 99 dogs 2026 — ≥ 9.54% (Moderate) · 99% complete · 7 dogs ## Founders 169 founders in the reference sample's known ancestry; the five most influential carry 5.32% of the known genome. Effective founders (fe): 55.54 — the number of equally contributing founders that would produce the same genetic diversity as the breed's 169 real, unevenly contributing founders. Founder genome equivalents (fg): 4.41 — a lower, more realistic figure that also accounts for genetic material lost to drift over generations; fg is normally lower than fe, never more than the number of founders whose lines still survive. - **輝初千代号 豊玄荘:** [1.43% mean contribution](https://nihonken.org/pedigree/dogs/20167761-2dfb-4d5d-bd51-973c0239ffea) - **照峰女号 一丸犬舎:** [1.11% mean contribution](https://nihonken.org/pedigree/dogs/6dacf4dd-99ef-4243-abd8-c75fc0cd320f) - **龍雲号 備中清水荘:** [1.04% mean contribution](https://nihonken.org/pedigree/dogs/a6128d78-0427-468f-9cc4-10c1d2a883a1) - **麗峰女号 備後荘:** [1.02% mean contribution](https://nihonken.org/pedigree/dogs/8b7f77be-4063-4a41-aae1-5f7e3e1f7fcc) - **栃春三女号 八幡浜新川荘:** [0.72% mean contribution](https://nihonken.org/pedigree/dogs/47f83262-8389-4c07-ab62-5170386b5f8f) - **Nagisa:** [0.67% mean contribution](https://nihonken.org/pedigree/dogs/9f3cc146-5e61-43b4-bc87-e2b024ccf3a4) - **富士嵐号 みるが丘荘:** [0.67% mean contribution](https://nihonken.org/pedigree/dogs/c5b30efa-84e6-4e59-b2ce-4d7c6dec5898) - **龍月号 忠道荘:** [0.65% mean contribution](https://nihonken.org/pedigree/dogs/6d28d53b-175e-4410-88ad-ea891156d2c0) - **夕月号 伊予竜宮荘:** [0.65% mean contribution](https://nihonken.org/pedigree/dogs/e2529133-3bb3-464c-a3e9-2cf1cee74022) - **桂姫号 須崎一条荘:** [0.64% mean contribution](https://nihonken.org/pedigree/dogs/6b645bae-d071-48e5-b8b1-947a401f570f) - **鉄山女号 高輪犬舎:** [0.6% mean contribution](https://nihonken.org/pedigree/dogs/69a70ec3-3e24-4faf-a3ed-61c36357d61a) - **銀汀女号 絹川荘:** [0.52% mean contribution](https://nihonken.org/pedigree/dogs/0a354530-51f7-4f6e-9e90-001c13ffcf61) - **Hidenobu go Awa Tosasou:** [0.47% mean contribution](https://nihonken.org/pedigree/dogs/bc571cc6-3e3b-4957-8efd-25c697534631) - **秋雲号 秋雲荘:** [0.41% mean contribution](https://nihonken.org/pedigree/dogs/4840f2ea-78bb-405f-bc79-09b8557f493c) - **Kasamatsu sou:** [0.4% mean contribution](https://nihonken.org/pedigree/dogs/79223a6e-585c-4fa8-9add-84f5d61805bc) - **恒美女号 松木荘:** [0.4% mean contribution](https://nihonken.org/pedigree/dogs/a372a2e6-5589-4a04-922c-1511bdee21a7) - **春秀三女号 二美荘:** [0.38% mean contribution](https://nihonken.org/pedigree/dogs/34ac4089-68e5-4fb6-97e9-50c61c372476) - **太智寿号 大下荘:** [0.38% mean contribution](https://nihonken.org/pedigree/dogs/f3d6672e-985c-443c-87d9-779daf3f51c7) - **晃峰女号 羽曳野荘:** [0.37% mean contribution](https://nihonken.org/pedigree/dogs/24308ec6-40d0-4650-8b42-4e6120c26ceb) - **吉玉女号 鬼城犬舎:** [0.35% mean contribution](https://nihonken.org/pedigree/dogs/8f5c71b7-0339-4085-82b6-e7e4f7e1d1db) ## 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. ## How to cite Nihon Ken Pedigree Database (2026). Shikoku Ken breed report 2026. https://nihonken.org/pedigree/breeds/shikoku/report/2026. Accessed 2026-10-13. Licensed CC BY 4.0. ## Caveats Every COI figure is a floor: pedigrees are incomplete. 1.7% of the reference dogs' ancestry is unknown and 72.2% lies beyond 10 generations; fe and fg describe the known part. The reference sample is 500 of 1165 dogs born since 2018. --- **Navigate:** [Home](https://nihonken.org/pedigree/?format=md) · [Search](https://nihonken.org/pedigree/browse?format=md) · [Litters](https://nihonken.org/pedigree/litters?format=md) · [Breeders](https://nihonken.org/pedigree/breeders?format=md) · [LLM guide](https://nihonken.org/pedigree/llms.txt) _Search by name: https://nihonken.org/pedigree/browse?q=NAME&format=md_