Gunji Koizumi · Lineage tree

Also known as

G.K.

Description

Japanese judoka and jujutsuka. Founder of the Budokwai (1918), known as the 'Father of British Judo.' Studied Tenjin Shinyo-ryu under Nobushige Tago, later Shin-Shin-Ryu under Yamada Nobukatsu and Akishima-Ryu under Akishima Tsunejiro. Converted to Kodokan Judo in 1920 under Jigoro Kano. Co-founded the British Judo Association (1948) and European Judo Union (1948). Author of 'My Study of Judo' (1960). Held 8th dan Kodokan.

Teachers (3)

• 
  Tago Nobushige

  sports_martial_artsTenjin Shin'yō-ryū Confirmed

  Confirmed

  Documented in Gunji Koizumi's own autobiographical account in 'My Study of Judo' (1960)

  The evidence establishes the claim: it is sufficient and consistent, and any conflicting evidence is resolved.

  location_onSeibukan badge (1901)

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Documented in Gunji Koizumi's own autobiographical account in 'My Study of Judo' (1960)

  visibilityFirst-hand

  “Moving to Tokyo, and under the stress of the usual schoolboy feuds, I took up Tenshin-Shinyo-Ryu Ju Jutso under NOBUSHIGE TAGO, who was quite an impressive figure with a long grey beard”

  — Koizumi, Gunji. (1960). My Study of Judo - The Principles And The Technical Fundamentalslink history info

  “In 1901, he started practising jujutsu under Tago Nobushige at the Tenjin Shinyo-ryu.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info
• person
  Yamada Nobukatsu

  (1904)

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Documented in Gunji Koizumi's autobiographical account and Wikipedia

  visibilityFirst-hand

  “In 1904, in Fusan, Korea, I attended the Kenjutsu and Ju JUTSU school conducted by an ex-samurai of the Owari clan, Sensei NOBUKATSU YAMADA and learned the techniques of SHIN-SHIN-RYU, JU JUTSU and KATSU.”

  — Koizumi, Gunji. (1960). My Study of Judo - The Principles And The Technical Fundamentalslink history info

  “In 1904, he trained under Yamada Nobukatsu, a former samurai.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info
• person
  Akishima Tsunejiro

  (1905–1906)

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Documented in Gunji Koizumi's autobiographical account and Wikipedia

  visibilityFirst-hand

  “During a four months' stay in Singapore from November 1905 to February 1906, I helped Sensei T. Akishima in conduct of his Ju Jutsu school and was taught the 144 techniques of AKISHIMA-RYU and KATSU.”

  — Koizumi, Gunji. (1960). My Study of Judo - The Principles And The Technical Fundamentalslink history info

  “While in Singapore in 1905, he trained under Tsunejiro Akishima.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

Lineage

• Tenjin Shin'yō-ryūTago Nobushige ← Jinbo Genjūrō ← Sakurai Kunzō ← Iso Masatari Mataemon · 4 generations

Ranks (5)

• sports_martial_artsKōdōkan Jūdō

  military_tech2 dan Confirmed

  Confirmed

  Independent sources state it.

  The evidence establishes the claim: it is sufficient and consistent, and any conflicting evidence is resolved.

  Dan-Kyu System (1920)

  granted by Kanō Jigorō, Kodokan

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Independent sources state it.

  “In July 1920, Jigoro Kano, founder of the Kodokan, visited the Budokwai while on his way to the Olympic Games in Antwerp. After some discussion, Koizumi and Yukio Tani agreed to change to the judo system, and Kano awarded them 2nd dan judo certifications.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

  “In 1920 Jigoro Kano visited the Budokwai, on his way to the 1920 Olympic Games as Head of the Japanese Delegation”

  — Callan, Mike. (2011). Gunji Koizumi: The Father of European Judolink info

  military_tech4 dan Probable

  Probable

  Documented in Wikipedia and Budokwai historical sources

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  Dan-Kyu System (1932)

  granted by Kodokan

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  1 source expand_more

  fact_check

  Documented in Wikipedia and Budokwai historical sources

  “In 1932, he was promoted to 4th dan in judo.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

  military_tech6 dan Probable

  Probable

  Documented in Wikipedia and academic sources

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  Dan-Kyu System (1948)

  granted by Kodokan

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  1 source expand_more

  fact_check

  Documented in Wikipedia and academic sources

  “In 1948, Koizumi was promoted to 6th dan in judo.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

  military_tech7 dan Probable

  Probable

  Documented in Wikipedia and academic sources

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  Dan-Kyu System (1951)

  granted by Kodokan

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  1 source expand_more

  fact_check

  Documented in Wikipedia and academic sources

  “In 1951, he attained the rank of 7th dan in judo.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

  military_tech8 dan Probable

  Probable

  Awarded 17 November 1962 per Japanese sources (Kudo 1965); confirmed by Black Belt Magazine Nov 1965

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  Dan-Kyu System (1962-11-17)

  granted by Kodokan

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Awarded 17 November 1962 per Japanese sources (Kudo 1965); confirmed by Black Belt Magazine Nov 1965

  “1962年11月17日付で8段位を拝受”

  — 小泉軍治 - Wikipedia (Japanese). Wikipedia (Japanese) link history info

  “He held the rank of 8th dan in judo.”

  — Gunji Koizumi - Wikipedia (English). Wikipedia (English)link history info

Offices held (1)

• corporate_farePresidentBudokwai Probable

  Probable

  Wikipedia only.

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  1918

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  1 source expand_more

  fact_check

  Wikipedia only.

  “Koizumi became the first president of the Budokwai and Yukio Tani the first chief judo instructor.”

  — Wikipedia contributors. (2026). Budokwai. Wikipedia (English)link history info

Students (3)

• 
  Moshé Feldenkrais

  sports_martial_artsKōdōkan Jūdō Confirmed

  Confirmed

  Feldenkrais's own preface to Higher Judo acknowledges Koizumi as someone he learned a great deal from (primary); de Crée (2013) confirms from the Budokwai dan-rank register that Feldenkrais joined the Budokwai in 1948; two other sources place him studying judo under Koizumi at the London Budokwai.

  The evidence establishes the claim: it is sufficient and consistent, and any conflicting evidence is resolved.

  location_onBudokwai badge (1948–1950)

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  5 sources expand_more

  fact_check

  Feldenkrais's own preface to Higher Judo acknowledges Koizumi as someone he learned a great deal from (primary); de Crée (2013) confirms from the Budokwai dan-rank register that Feldenkrais joined the Budokwai in 1948; two other sources place him studying judo under Koizumi at the London Budokwai.

  “He took judo classes with Gunji Koizumi at the London Budokwai”

  — Who Was Moshe Feldenkrais?link history info

  “After leaving the service in 1945, he moved to London and joined the Budokwai, where he studied judo under the great master G. Koizumi.”

  — Moti Nativ. (2017). On Better Judo: Moshe Feldenkrais on Learning, Balance, and Masterylink history info

  “Feldenkrais only joined the Budōkwai in 1948, thus well after he had left France and had moved to England.”

  — Carl de Crée. (2013). Shōnen Jūdō-no-kata ["Forms of Jūdō for Juveniles"] - an experimental Japanese teaching approach to Jūdō skill acquisition in children considered from a historic-pedagogical perspective - part IIlink info

  visibilityFirst-hand

  “It has been my good fortune to meet Mr. G. Koizumi, from which I have learned a great deal. The clarity of his knowledge is equal to the generosity with which he imparts it”

  — Moshe Feldenkrais; Elizabeth Beringer. (2010). Higher Judo: Groundworkinfo

  “In London he deepened his friendship and judo practice with legendary practitioners Gunji Koizumi and Trevor Leggett.”

  — Moshe Feldenkrais; Elizabeth Beringer. (2010). Higher Judo: Groundworkinfo
• 
  Sarah Mayer

  sports_martial_artsKōdōkan Jūdō Confirmed

  Confirmed

  Wikipedia states Mayer first trained in judo by Gunji Koizumi at the Budokwai in the 1920s; Callan/Heffernan/Spenn confirm the ladies' classes were taught by Koizumi at the Budokwai, which Mayer joined in 1926.

  The evidence establishes the claim: it is sufficient and consistent, and any conflicting evidence is resolved.

  location_onBudokwai badge (1926–1933)

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  2 sources expand_more

  fact_check

  Wikipedia states Mayer first trained in judo by Gunji Koizumi at the Budokwai in the 1920s; Callan/Heffernan/Spenn confirm the ladies' classes were taught by Koizumi at the Budokwai, which Mayer joined in 1926.

  “Mayer first trained in judo by Gunji Koizumi at the Budokwai in the 1920s.”

  — Wikipedia contributors. (2026). Sarah Mayer - Wikipedia (English). Wikipedia (English)link history info

  “In 1926, Mayer [...] first joined the Budokwai as the thirty-first female member. [...] The ladies' classes, at that time, were taught by Koizumi, the founder, and Tani Yukio”

  — Callan, Mike; Heffernan, Conor; Spenn, Amanda. (2018). Women's Jūjutsu and Judo in the Early Twentieth-Century: The Cases of Phoebe Roberts, Edith Garrud, and Sarah Mayer link info
• person
  Trevor Leggett

  sports_martial_artsKōdōkan Jūdō Probable

  Probable

  Single source.

  The evidence favours the claim and nothing credible contradicts it, but it falls short of establishing it.

  location_onBudokwai badge

  fact_checkassessed by FSMverified

  Frederico Muñoz

  Researcher, Martialis

  1 source expand_more

  fact_check

  Single source.

  “At the age of 16, therefore, the sport he chose was judo and he started taking lessons at the London Budokwai. After training under the famous judo masters Yukio Tani and Gunji Koizumi, he made swift progress”

  — Brian N. Watson. (2008). Judo Memoirs of Jigoro Kanoinfo

Sources

Identifiers