Within a few years after the foundation of the Scouting Movement in England by Lord Baden-Powell in 1907, the spirit and practice of Scouting spread to most of the English-speaking world and to several European countries. In some countries it took a few more years before "official" Scouting rose out of the confusion caused by a variety of imitative organizations.

The earliest Japanese translation of Scouting for Boys appeared in late 1910 and unofficial and unrecognized troops also soon appeared. All of these proved short-lived except for one troop organized in the Bluff area of Yokohama by Clarence Griffin. The troop was registered with the Scout Headquarters in London and thus became the recognized beginning of the Scout Movement in Japan.

Japan's first scoutmaster, Clarence Griffin, was born in Northern Ireland in 1873 and was the only son of British parents. John Thomas Griffin, Clarence’s father, soon moved to Japan to begin business and Clarence remained in Northern Ireland with his mother, Sara Louise, until 1875 when the family reunited in Yokohama.

As an adult, Clarence Griffin was very active in the foreign community of Yokohama, also serving as a local Sunday School teacher. Sometime in late 1911, Clarence was reading an American Scouting magazine when he came across a page that read; "Are you waiting for someone to start a Boy Scout troop in your community? Why wait? Start one yourself!" This was all the prompting that Clarence needed and his mind was made up to begin a Troop and, during the final months of 1911 a group of boys that would become Japan's first recognized Scout troop was already busy practicing their Scouting skills. On February 2, 1912 Clarence Griffin and 18 boys, mostly British and students from the local boys school, St. Joseph College, gathered at the Gaiety Theater on the Bluff to demonstrate the Scouting skills they were practicing and to officially celebrate the beginning of the "First Yokohama Troop."

On April 2, 1912 Baden-Powell was welcomed on his arrival Japan at the port of Yokohama by Clarence Griffin and the Scouts of the First Yokohama. Aboard a small steamer, in full uniform and waving the Union Jack, they sailed out to greet the surprised Baden-Powell. The "First Yokohama Troop" was officially registered with the Imperial Headquaters of The Boy Scouts Association (British Scout Headquarters) as a British troop abroad, or as such groups were referred to then, as "British Scouts in Foreign Countries", and its membership was "officially" restricted to British nationals. Clarence Griffin was presented a Scoutmaster's Warrent by Baden-Powell.

However, as mentioned above, the boys of the First Yokohama attended St. Joseph College and many of their classmates, who came from many countries around the world, also wanted to be Scouts. The nationality regulation was "loosely" enforced from the beginning but the majority of the boys in the First Yokohama at the time were, of course, British nationals, as only they could be registered as official members of the troop.

The British boys of St. Joseph College and the Bluff community continued to enjoy the benefits of Scouting for several years. However, the widespread disruption of World War I steadily reduced the number of boys in the Troop, and in a letter to Baden-Powell in 1917 Clarence Griffin expresses his pride in knowing the Scouts that served bravely but would never again return to Yokohama. Following the end of the war, the troop again began to grow in size and by the spring of 1918 consisted of three Patrols and 39 boys. St. Joseph College also again began to swell with students coming from countries all over the world, most of them wishing they too could be Scouts alongside their British classmates.

In 1918, Brother Joseph Janning arrived in Japan as a missionary teacher at St. Joseph College. His attention was drawn to the fact the British boys living in Yokohama had been able to benefit by the experiences of Scouting, but the boys of other nationalities at the international school were not so fortunate. After discussions with Brother John-Baptist Gaschy, then Director of Saint Joseph College, the idea of a scout troop open to all, regardless of nationality, was proposed to the School Council. The suggestion was enthusiastically adopted, and it was decided to confide the leadership of the Yokohama "International" troop to Brother Joseph Janning, Brother William Abromitis, and Brother Edward Sandrock.

The "Second Yokohama Troop" was born and the first meeting of the new group consisted of the 36 boys already involved in Scouting in the "British" troop and a few of their classmates. However, by the end of the month the number grew to over 70 boys and by the end of the year there were more than 150 Scouts in the troop.

At this early stage of its existence, the Troop had neither official name nor official recognition, as it could not be officially registered with either the British or American Scout organizations or, in fact, any of the national scout organizations of the day because of the nationality regulation in force at the time.

The "International" Troop continued to grow and also made efforts to help other developing groups of Scouts. In 1920, Richard Suzuki, the son of a Japanese father and British mother from Yokohama and a patrol leader in the International Troop, was returning to England for study when he was met onboard ship by Toyomatsu Shimoda and Hiroshi Koshiba. Shimoda and Koshiba were both going on private business to England, but were also planning to attend the First World Jamboree. When they learned that Richard was a Scout, they asked him to join them; Being the only Scout-age participant Richard carried the Japanese placard in the opening ceremonies.

The Great Earthquake of 1923 devastated Yokohama. Clarence Griffin was found barely breathing by surprised Scouts as they helped with rescue work in the aftermath of the destruction. Clarence Griffin was transported to Kobe where he began to recover from his injuries. At the same time both St. Joseph College and the Troop also went into "exile" to Kobe where Scouting activities were continued without interruption as Yokohama, and the school, was being rebuilt. In early 1925, only a few months after the earthquake, the international school and the Troop returned to Yokohama. As the boys returned to Yokohama they renamed the group the "Third Yokohama Troop" in recognition of this third major event faced by Yokohama’s Scouts. In the meanwhile, the Boy Scouts International Bureau (now the World Organization of the Scouting Movement [WOSM]) had been established in London as a result of the First World Jamboree. Bro. Janning had been in direct communication with Baden-Powell about the dilemma of groups such as the one at St. Joseph. At the direction of B-P, the troop found in the Bureau an opportunity for official recognition and had the honor of receiving the first direct Charter issued by the Bureau. The Charter officially allowed the Troop to enroll Scouts of “mixed” nationality. The Yokohama Troop at St. Joseph College was now recognized as the World’s first officially chartered “International” Boy Scout Troop. The original of this Charter, bearing the signature of Lord Baden-Powell, is preserved in the Archives at the I.B.S. Headquarters. At the time the Charter was issued the Troop was still unofficially calling itself the "Third Yokohama Troop", the "International Troop" or simply the "St. Joseph Troop."

During the latter part of the 1930's and early 1940's, the world political situation gradually affected St. Joseph College and the International Boy Scout Troop. Since some families among the foreign community in Yokohama left the country, and many of the dual- or multiple-nationality families began to stress their Japanese side, the student population and the number of Scouts in the Troop decreased. The Boy Scouts of Japan were officially disbanded by order of the militaristic government. This did not directly concern the International Boy Scout Troop; but the Leaders did notice that more and more they seemed to be kept under surveillance by the police when they went hiking in the area around the city.

Then came Pearl Harbor. Immediately after that on December 8, 1941, the American Marianists on the faculty of St. Joseph College were taken into custody as "enemy aliens" and interned at the Negishi Internment Camp at the site of the Negishi Race Track. It may have been coincidence, but the first to be interned were the Leaders of the Scout Troop.

Shortly after that, the Japanese Military ordered all foreigners to leave the city, and took over the buildings and property of the College. As a "compensation", the school was allowed to re-open in an abandoned hotel in the small mountain town of Gora, Hakone, where quite a few of the foreign families were now living. Scouting, as a school activity, continued -- with no uniforms and very little out-door activity. In later years, they told of practicing knot-tying, first-aid and other Scouting skills while sitting on the stairways of the temporary school building.

When they war ended and St. Joseph College was able to return to Yokohama in 1945, both the school and the Scouts received assistance and encouragement from the American Occupation Forces. Within a short time, the U.S. Forces opened schools for their own children and the Boy Scouts of America soon set up two Troops in Yokohama under the Far East Council. Because of this, when several American officers and non-commissioned officers offered their help to the Scout Troop at St. Joseph College, (knowing Scouting only as the Boy Scouts of America) they referred to the International Troop as "Yokohama Troop 3", sometimes even using the rather clumsy expression "International Boy Scouts of America, Yokohama, Troop 3", adding confusion to the list of names  that were used to refer to the Troop at the time.

For about a year, a young American serviceman, Pfc. John Linden, served as a Scoutmaster for the Troop. Soon, however, Marianist Brother Francis Tribull, who had been an Assistant Scoutmaster before the War, returned to St. Joseph College and was appointed Scoutmaster, with Brother Leo Kraft as Assistant Scoutmaster.

Gradually, the usage of "Yokohama Troop 3" reverted to the proper "International Boy Scouts." It was also at this time that, in a letter to the Troop, the Secretary General of the World Scout Bureau corrected the naming of the group, ending the confusion once and for all. In the letter, the Secretary General recognized and approved the right of this Scout Troop to use the name "International Boy Scouts, Troop 1." A post-war Cub Pack was started in 1952, with Brother Leo as Cubmaster. Brother Tribull, busy with school administration turned the Scoutmastership over to Brother Santos Montoya in 1953.

The International Boy Scouts, Troop 1, grew in numbers and flourished as one of the main activities in the school, cooperating with both the Japanese Boy Scouts and the American Scouts' Far East Council in Camporees, Rallies and parades. In 1956 and 1959 the Troop attended the First and Second Nippon Jamborees on an equal basis with Troops invited to attend from overseas.

During 1958-9, the Scout Leaders under direction from the World Scout Bureau and with the cooperation of the Senior Scouts, prepared a SCOUT HANDBOOK, which included the design of the new Scout uniforms and new distinctive Scout Badges. After the final corrections to the HANDBOOK were made personally by the Secretary General of the World Scout Bureau, the HANDBOOK was finally published in 1961; but the newly designed uniforms and badges were worn at the 1959 Jamboree.

After nearly 100 years on the Bluff, Saint Joseph International School closed, sadly, in 2000. The International Boy Scouts, Troop I under the direction of the I.B.S. Executive Council, however, continues to offer the boys of Yokohama an "international" scout program ranging from Beaver and Cub Scouts through Boy and Senior Scouts. Despite the disruptions brought to Japan and the world by World Wars, fires, earthquakes, and other economic disasters, the International Boy Scouts, Troop 1, or simply the IBS, as it is often referred to now, has continued, uninterrupted since it's beginning, to offer the program of Scouting to boys of many nationalities. The Troop is justly proud of its status as the world's first "international" Boy Scout Troop, authorized by official Charter signed personally by Lord Baden-Powell and issued directly by the Boy Scouts International Bureau to accept Scouts of all nations.

１９０７年にBaden-Powell卿によって英国でボーイスカウト活動が始まったあと何年かの間に、スカウト活動の精神や訓練はほとんどの英語圏の国やヨーロッパの数カ国に広まった。いくつかの国では、“公認の”スカウト活動は様々な機関が真似をし、混乱する中で発起するのにいくらかの年数がかかった。

最初の“Scouting for Boys”の日本語訳も１９１０年の後半に出現し、他の非公式の隊もまたすぐに現れた。これらの全ては長続きしなかったが横浜で最初のスカウト隊の一つである“グリフィン隊” は組織化し、イギリスでのボーイスカウト本部に登録されていた。日本におけるボーイスカウト運動の創始である。

日本での最初のスカウトマスターであるクリアランス・グリフィンは１８７３年（明治６年）に、英国人の両親の１人息子として父ジョン・トーマス・グリフィンと母サラ・ルイザの間に北アイルランドで生まれた。　父は早くから横浜で貿易商を営んでおり、彼は母とともに北アイルランドで生活をしていたが、その後１８７５年（明治８年）一家は横浜に来て生活することになった。 グリフィン氏はとても活動的で地域の日曜学校で奉仕をしていた。グリフィンがスカウト活動を始めるに至った動機は、アメリカのスカウト雑誌に、「あなたはあなたのいる町で誰かがボーイスカウト隊を作るのを待っているのですか。待っているよりも、あなた自身で始めなさい」と言うの言葉を見て、ボーイスカウト隊を作る事を決意したという。かくして 山手の男子校であったSt. Joseph Collegeの生徒の中心となり１９１１年１２月２日(明治４４年) 横浜山手のゲーテ座において発隊式を挙げた。組織、内容はまったくイギリスのそれと同じでありはやくもすでにイギリス本部に登録をしていた。Scouting For Boysが刊行されて３年目にして、又少年団日本連盟が結成される１１年前に日本にこの活動が行われていたのである。　

１９１２年４月２日Baden-Powell卿が来日し、グリフィン氏や横浜一隊のスカウト達によって歓迎された。Baden-Powell卿は直にグリフィン氏のスカウトマスター認定書を手渡した。

スカウト本部にBritish Scouts in Foreign Countries (海外での英国スカウト)として登録された。つまり、それは英国スカウトとして公式に英国の国家の一員として制限されていた。

しかしながらSt. Joseph Collegeに存在した横浜一隊の少年達とそのクラスメイトの多くは世界中のいろいろな国の出身でありながら、スカウトになる事を希望していた。国籍の規制は最初から“緩く”施行されたが、横浜一隊の少年達の大多数はもちろん公式メンバーとして登録する事が可能であった英国人国籍がほとんどであった。

St. Joseph Collegeや山手の地域の英国人少年達は何年間かはスカウト活動の特権を楽しみ続けた。第一次大戦の広範囲に及ぶ活動の中断により確実に参加少年の人数は減少し、1917年のBaden-Powellの書簡にはグリフィン氏が勇敢にもスカウト活動に奉仕をしている事を知り大変誇りに思いながらも、二度と横浜に戻る事が無いと表してあった。しかしながら戦争の終結近くである１９１８年の春までには団は再び３人のパトロールリーダーと３９人の少年達を含んだ元の規模に戻っていった。St. Joseph Collegeはまた世界各地の国々から戻ってきた生徒たちであふれ始め彼らのほとんどは再び英国人のクラスメイトと共に行動する事のできる事を望んでいた。

１９１８年にはBrother Joseph JanningがSt. Joseph Collegeの宣教教師として来日した。彼の関心は横浜在住の英国人少年達がスカウト活動の経験を受ける事のできる特権を得ることができるのに、インターナショナルスクールの他の国籍の少年達にはできないという事実が気にかかっていた。St. Joseph Collegeの学長であるBrother John-Baptist Gaschyはスカウト活動が国籍に関わらず全ての少年達に平等に開かれるべきだという考えをもちそれを学内評議会に提案をした。提案は熱狂的に採用され、Brother Joseph Janning、 Brother William AbromitisおよびBrother Edward Sandrockに横浜“国際”第一隊のリーダーシップを任命する事が決められた。

次期横浜国際第一隊が設立され、既に活動を始めていた英国人の横浜一隊とそのクラスメイトを含んだ３６人の少年達の新しいグループに加わり、最初のミーティングが開かれた。その人数はその月の終わりには７０人に増え、その年の終わりまでにはなんと１５０人以上もの人数にふくれあがったのだ。

存在の初期の段階では隊は公式な名前も持たず、英国のものでもアメリカのものでもない機関として公式に登録する事ができなかったため、また事実当時の国籍の規則のため当時該当する国内の機関がなかったため、公式な認証もされていなかった。

横浜国際第一団はどんどん拡大していき、また他のスカウトの発展しつつあるグループをも支援する努力もしていた。１９２０年横浜出身の日本人の父親と英国人の母親を持ち団の中でパトロールリーダーをしていたRichard Suzukiは、勉学の為に英国に渡る船の上で下田豊松と小柴博と出会った。下田と小柴は二人とも個人的な仕事のためとまた第１回世界ジャンボリーに参加する目的で英国に渡航していた。Richardがスカウトであるという事がわかると二人は彼にジャンボリーへ参加し、唯一の現役スカウトの参加者として開会式で日本のプラカードを持つ事を依頼した。

１９２３年の関東大震災が横浜を襲い多大な被害を持たらせた。グリフィン氏は凄まじい破壊の余波の中で手伝いをしているスカウト達によって息絶えようとしていた所発見された。グリフィン氏は神戸に移住し負傷から回復をし始めた。同時にSt. Joseph Collegeと団は、横浜であることや学校であることとして妨害される事無くスカウトの活動を続ける事のできる神戸へ避難し再結成を試みた。１９２５の初期、震災のわずか数ヶ月後インターナショナルスクールと団は横浜に戻ってきた。少年達が横浜に戻ってくると彼らは自分たちのグループを“横浜第３隊”と名付け、この第３の横浜のスカウトによって表面化したこの第３の大きなイベントを認識するグループを発足した。同時にボーイスカウト国際事務局 (WOSMの世界スカウト事務局の先駆) が第１回世界ジャンボリーの結果としてロンドンに設立された。Bro. JanningはBaden-Powellと直々に連絡をとりあいSt. Joseph Collegeでのと同じグループのジレンマについて話した。

Baden-Powellの指導で隊は事務局の中で公式な承認を得る機会を見いだし、初の事務局発行の直の認証を受けるという名誉を受けた。認証は公式には隊に“混合の”国籍のスカウトの入団を許可した。横浜隊は現在世界で最初の公式な認証を受けた“国際”ボーイスカウト隊という称号をうけることとなった。この認証の原文はBaden-Powell卿の署名入りでI.B.S.本部の記録保存庫の中に保管されている。憲章が発行された時、隊はまだ横浜第3隊または単純にSt. Joseph隊と非公式に呼ばれていた。隊への書簡の中には世界スカウト機構事務総長がその団体の名付けを訂正しており、 本隊が“国際ボーイスカウト第一団”という名前を使う権利を承認、証明している。

１００年近くたち、St. Joseph International Schoolが２０００年に閉校した。I.B.S. Executive Committee (I.B.S. 実行委員会) の指揮下の国際ボーイスカウト第一団はビーバー、カブスカウトからボーイスカウト、シニアスカウトまでの“国際”スカウトプログラムを横浜の少年達に提供し続けている。世界大戦、火事、震災そしてその他の経済災害が日本にもたらした大きな打撃にもかかわらず、国際ボーイスカウト第一団は現在ではI.B.S.として親しまれているが、初期の混乱にもめげず存続し続けて多国籍の少年達にスカウト活動のプログラムを提供し続けている。本隊はBaden-Powell卿の署名付きの公式認証を公認され、全ての国のスカウトを受け入れる少年スカウトの国際事務局によって直に発行された世界初の国際ボーイスカウト団である事をまさに誇りとしていると言える。