今日は、明治時代後期の1911年（明治44）に、「日英同盟」の改定（第三回日英同盟協約）が調印され、アメリカが交戦相手国の対象外に定められるなどして、継続更新された日です。

　「日英同盟」（にちえいどうめい）は、明治時代後期の1902年（明治35）1月30日に、イギリスの首都ロンドンで、日本駐英公使林董とイギリス外相ランズダウンとの間で調印された、イギリスと日本の二国間軍事同盟でした。日本の朝鮮・中国における権益、英国の中国における権益を相互に認め、アジアにおけるロシアの膨張に備えることを共同の目的とし、締約国の一方が２ヵ国以上と交戦の場合、他方は参戦の義務を負うものとします。
　その後、1905年（明治38）改定の第二回協約では、１国以上と交戦した場合は、同盟国はこれを助けて参戦するよう変更されました。また、1911年（明治44）改定の第三回協約では、アメリカが交戦相手国の対象外に定められるなどして継続更新され、1914年（大正3）に起こった第一次世界大戦では、日本はこの協約に基づき、連合国の一員として参戦します。
　しかし、1921年（大正10）のワシントン海軍軍縮会議の結果調印された四カ国条約成立に伴って、1923年（大正12）に失効しました。
　以下に、3回の「日英同盟協約」を掲載しておきますので、ご参照下さい。

 

The Anglo-Japanese Alliance, January 30,1902

The governments of Great Britain and Japan, actuated solely by a desire to maintain the status quo and general peace in the Extreme East, being moreover specially interested in maintaining the independence and territorial integrity of the Empire of China and the Empire of Korea, and in securing equal opportunities in those countries for the commerce and industry of all nations, hereby agree as follows:

ARTICLE I

　The High Contracting Parties, having mutually recognized the independenceof China and Korea, declare themselves to be entirely uninfluenced by anyaggressive tendencies in either country. Having in view, however, theirspecial interests of which those of Great Britain relate principally toChina, while Japan, in addition to the interests which she possesses inChina, is interested in a peculiar degree politically as well as commerciallyand industrially in Korea, the High Contracting Parties recognise thatit will be admissible for either of them to take such measures as may beindispensable in order to safeguard those interests if threatened eitherby the aggressive action of any other Power, or by disturbances arisingin China or Korea, and necessitating the intervention of either of theHigh Contracting Parties for the protection of the lives and property ofits subjects.

ARTICLE II

If either Great Britain or Japan, in the defence of their respective interestsas above described, should become involved in war with another Power, theother High Contracting Party will maintain a strict neutrality, and useits efforts to prevent other Powers from joining in hostilities againstits ally.

ARTICLE III

If in the above event any other Power or Powers should join in hostilitiesagainst the Ally, the other High Contracting Party will come to its assistanceand will conduct the war in common, and make peace in mutual agreementwith it.

ARTICLE IV

The High Contracting Parties agree that neither of them will, without consulting the other, enter into separate arrangements with another Power to the prejudice of the interests above described.

ARTICLE V

Whenever, in the opinion of either Great Britain or Japan, the above-mentionedinterests are in jeopardy, the two Governments will communicate with oneanother fully and frankly.

ARTICLE VI

The present Agreement shall come into effect immediately after the dateof its signature, and remain in force for five years from that date. Incase neither of the High Contracting Parties should have notified twelvemonths before the expiration of the said five years the intention of terminatingit, it shall remain binding until the expiration of one year from the dayon which either of the High Contracting Parties shall have denounced it.But if, when the date fixed for its expiration arrives, either Ally isactually engaged in war, the alliance shall, ipso fact, continue until peace is concluded.  

 【日本語訳文】 

第一回日英同盟協約（第一囘同盟協約，日英協約）

明治三十五年一月三十日倫敦ニ於テ調印（英文）

同年二月十二日官報彙報欄掲載

（譯文）

日本國政府及大不列顛國政府ハ偏ニ極東ニ於テ現狀及全局ノ平和ヲ維持スルコトヲ希望シ且ツ淸帝國及韓帝國ノ獨立ト領土保全トヲ維持スルコト及該二國ニ於テ各國ノ商工業ヲシテ均等ノ機會ヲ得セシムルコトニ關シ特ニ利益關係ヲ有スルヲ以テ茲ニ左ノ如ク約定セリ

第一條　兩締約國ハ相互ニ淸國及韓國ノ獨立ヲ承認シタルヲ以テ該二國孰レニ於テモ全然侵略的趨向ニ制セラルヽコトナキヲ聲明ス然レトモ兩締約國ノ特別ナル利益ニ鑑ミ卽チ其利益タル大不列顛國ニ取リテハ主トシテ淸國ニ關シ又日本國ニ取リテハ其淸國ニ於テ有スル利益ニ加フルニ韓國ニ於テ政治上竝ニ商業上及工業上格段ニ利益ヲ有スルヲ以テ兩締約國ハ若シ右等利益ニシテ別國ノ侵略的行動ニ因リ若クハ淸國又ハ韓國ニ於テ兩締約國孰レカ其臣民ノ生命及財產ヲ保護スル爲メ干渉ヲ要スヘキ騷擾ノ發生ニ因リテ侵迫セラレタル場合ニハ兩締約國孰レモ該利益ヲ擁護スル爲メ必要缺クヘカラサル措置ヲ執リ得ヘキコトヲ承認ス

第二條　若シ日本國又ハ大不列顛國ノ一方カ上記各自ノ利益ヲ防護スル上ニ於テ別國ト戰端ヲ開クニ至リタル時ハ他ノ一方ノ締約國ハ嚴正中立ヲ守リ倂セテ其同盟國ニ對シテ他國カ交戰ニ加ハルヲ妨クルコトニ努ムヘシ

第三條　上記ノ場合ニ於テ若シ他ノ一國又ハ數國カ該同盟國ニ對シテ交戰ニ加ハル時ハ他ノ締約國ハ來リテ援助ヲ與へ協同戰鬪ニ當ルヘシ講和モ亦該同盟國ト相互合意ノ上ニ於テ之ヲ爲スヘシ

第四條　兩締約國ハ孰レモ他ノ一方ト協議ヲ經スシテ他國ト上記ノ利益ヲ害スヘキ別約ヲ爲ササルヘキコトヲ約定ス

第五條　日本國若クハ大不列顛國ニ於テ上記ノ利益カ危殆ニ迫レリト認ムル時ハ兩國政府ハ相互ニ充分ニ且ツ隔意ナク通告スヘシ

第六條　本協約ハ調印ノ日ヨリ直ニ實施シ該期日ヨリ五箇年間効力ヲ有スルモノトス若シ右五箇年ノ終了ニ至ル十二箇月前ニ締約國ノ孰レヨリモ本協約ヲ廢止スルノ意思ヲ通告セサル時ハ本協約ハ締約國ノ一方カ廢棄ノ意思ヲ表示シタル當日ヨリ一箇年ノ終了ニ至ル迄ハ引續キ效力ヲ有スルモノトス然レトモ右終了期日ニ至リ同盟國ノ一方カ現ニ交戰中ナルトキハ本同盟ハ講和結了ニ至ル迄當然繼續スルモノトス

右證據トシテ下名ハ各其政府ヨリ正當ノ委任ヲ受ケ之ニ記名調印スルモノナリ

　一千九百二年一月三十日龍動ニ於テ本書二通ヲ作ル

　　大不列顛國駐剳日本國皇帝陛下ノ特命全權公使　林董　印

　　大不列顛國皇帝陛下ノ外務大臣　ランスダウン　印｛ランスダウンの右側に線あり｝

以書翰致啓上候陳者本日貴我兩名カ各其政府ヲ代表シテ締結シタル協約ニ關シ本使（本大臣）ハ左ノ如ク閣下ニ開陳スルノ光榮ヲ有シ侯

日本國政府（大不列顛國政府）ハ日本國（大不列顛國）海軍ノ平時ニ於テ成ルヘク大不列顛國（日本國）海軍ト協同ノ動作ヲ爲スヘキコトヲ承認ス而シテ其一方ノ軍艦カ他ノ一方ノ港内ニ於テ入渠スルコト及石炭搭載其他兩國海軍ノ安寧及効力ニ資スヘキ事項ニ付キテハ相互ニ便宜ヲ與フヘキコトヲ約諾ス

現下日本國及大不列顛國ハ孰レモ極東ニ於テ如何ナル第三國ヨリモ實力上優勢ナル海軍ヲ維持シツツアリ日本國（大不列顛國）ハ出來得ヘキ限リ極東ノ海上ニ於テ如何ナル第三國ノ海軍ヨリモ優勢ナル海軍ヲ集合シ得ル樣ニ維持スルニ努ムルコトヲ弛フスルノ意思ヲ有スルコトナシ

右得貴意候　敬具

   外務省編「日本外交年表竝主要文書」上巻より

 

AGREEMENT OF ALLIANCE OF 1905. (Agreement of Alliance between Japan and Great Britain, 1905, Second Anglo-Japanese Alliance) 

PREAMBLE.

The Governments of Japan and Great Britain, being desirous of replacing the Agreement concluded between them on the 30th January, 1902, by fresh stipulations, have agreed upon the following Articles, which have for their object; 

(a.) The consolidation and maintenance of the general peace in the regions of Eastern Asia and of India; 

(b.) The preservation of the common interests of all Powers in China by insuring the independence and integrity of the Chinese Empire and the principle of equal opportunities for the commerce and industry of all nations in China; 

(c.) The maintenance of the territorial rights of the High Contracting Parties in the regions of Eastern Asia and of India, and the defense of their special interests in the said regions:-- 

ARTICLE 1.

It is agreed that whenever, in the opinion of either Japan or Great Britain, any of the rights and interests referred to in the preamble of this Agreement are in jeopardy, the two Governments will communicate with one another fully and frankly, and will consider in common the measures which should be taken to safeguard those menaced rights or interests. 

ARTICLE 2.

If by reason of unprovoked attack or aggressive action, wherever arising, on the part of any Power or Powers either Contracting Party should be involved in war in defence of its territorial rights or special interests mentioned in the preamble of this Agreement, the other Contracting Party will at once come to the assistance of its ally, and will conduct the war in common, and make peace in mutual agreement with it. 

ARTICLE 3.

Japan possessing paramount political, military, and economic interests in Corea, Great Britain recognizes the right of Japan to take such measures of guidance, control, and protection in Corea as she may deem proper and necessary to safeguard and advance those interests, provided always that such measures are not contrary to the principle of equal opportunities for the commerce and industry of all nations. 

ARTICLE 4.

Great Britain having a special interest in all that concerns the security of the Indian frontier, Japan recognizes her right to take such measures in the proximity of that frontier as she may find necessary for safeguarding her Indian possessions. 

ARTICLE 5.

The High Contracting Parties agree that neither of them will, without consulting the other, enter into separate arrangements with another Power to the prejudice of the objects described in the preamble of this Agreement. 

ARTICLE 6.

As regards the present war between Japan and Russia, Great Britain will continue to maintain strict neutrality unless some other Power or Powers should join in hostilities against Japan, in which case Great Britain will come to the assistance of Japan, and will conduct the war in common, and make peace in mutual agreement with Japan. 

ARTICLE 7.

The conditions under which armed assistance shall be afforded by either Power to the other in the circumstances mentioned in the present Agreement, and the means by which such assistance is to be made available, will be arranged by the Naval and Military authorities of the Contracting Parties, who will from time to time consult one another fully and freely upon all questions of mutual interest. 

ARTICLE 8.

The present Agreement shall, subject to the provisions of Article 6, comme{sic} into effect immediately after the date of its signature, and remain in force for ten years from that date. 

In case neither of the High Contracting Parties should have notified twelve months before the expiration of the said ten years the intention of terminating it, it shall remain binding until the expirations of one year from the day on which either of the High Contracting Parties shall have denounced it. But if, when the date fixed for its expiration arrives, either ally is actually engaged in war, the alliances shall, ipso facto, continue until peace is concluded. 

In faith whereof, the Undersigned, duly authorized by their respective Governments, have signed this Agreement and have affixed thereto their Seals. 

Done in duplicate at London, the 12th day of August, 1905. 

[L.S.] (Signed) TADASU HAYASHI. 

Envoy Extraordinary and Minister Plenipotentiary of His Majesty the Emperor of Japan at the Court of St. James. 

[L.S.] (Signed) LANSDOWNE, 

 

第二回日英同盟協約

明治三十八年八月十二日倫敦ニ於テ調印（英文） 

同年九月二十七日官報彙報欄掲載 

（譯文） 

日本國政府及大不列顛國政府ハ一千九百二年一月三十日兩國政府間ニ締結セル協約ニ代フルニ新約款ヲ以テセムコトヲ希望シ 

（イ）東亞及印度ノ地域ニ於ケル全局ノ平和ヲ確保スルコト 

（ロ）清帝國ノ獨立及領土保全竝清國ニ於ケル列國ノ商工業ニ對スル機會均等主義ヲ確實ニシ以テ清國ニ於ケル列國ノ共通利益ヲ維持スルコト 

（ハ）東亞及印度ノ地域ニ於ケル兩締盟國ノ領土權ヲ保持シ竝該地域ニ於ケル兩締盟國ノ特殊利益ヲ防護スルコト 

ヲ目的トスル左ノ各條ヲ約定セリ 

第一條　日本國又ハ大不列顛國ニ於テ本協約前文ニ記述セル權利及利益ノ中何レカ危殆ニ迫ルモノアルヲ認ムルトキハ兩國政府ハ相互ニ充分ニ且隔意ナク通告シ其ノ侵迫セラレタル權利又ハ利益ヲ擁護セムカ爲ニ執ルヘキ措置ヲ協同ニ考量スヘシ 

第二條　兩締盟國ノ一方カ挑發スルコトナクシテ一國若ハ數國ヨリ攻撃ヲ受ケタルニ因リ又ハ一國若ハ數國ノ侵略的行動ニ因リ該締盟國ニ於テ本協約前文ニ記述セル其ノ領土權又ハ特殊利益ヲ防護セムカ爲交戰スルニ至リタルトキハ前記ノ攻撃又ハ侵略的行動カ何レノ地ニ於テ發生スルヲ問ハス他ノ一方ノ締盟國ハ直ニ來リテ其ノ同盟國ニ援助ヲ與ヘ協同戰鬪ニ當リ講和モ亦雙方合意ノ上ニ於テ之ヲ爲スヘシ 

第三條　日本國ハ韓國ニ於テ政事上、軍事上及經濟上ノ卓絶ナル利益ヲ有スルヲ以テ大不列顛國ハ日本國カ該利益ヲ擁護増進セムカ爲正當且必要卜認ムル指導、監理及保護ノ措置ヲ韓國ニ於テ執ルノ權利ヲ承認ス但シ該措置ハ常ニ列國ノ商工業ニ對スル機會均等主義ニ反セサルコトヲ要ス 

第四條　大不列顛國ハ印度國境ノ安全ニ繋ル一切ノ事項ニ關シ特殊利益ヲ有スルヲ以テ日本國ハ前記國境ノ附近ニ於テ大不列顛國カ其ノ印度領地ヲ擁護セムカ爲必要ト認ムル措置ヲ執ルノ權利ヲ承認ス 

第五條　兩締盟國ハ孰レモ他ノ一方ト協議ヲ經スシテ他國ト本協約前文ニ記述セル目的ヲ害スヘキ別約ヲ爲ササルヘキコトヲ約定ス 

第六條　現時ノ日露戰爭ニ對シテハ大不列顛國ハ引續キ嚴正中立ヲ維持シ若シ他ノ一國若ハ數國カ日本國ニ對シ交戰ニ加ハルトキハ大不列顛國ハ來リテ日本國ニ援助ヲ與へ協同戰鬪ニ當リ講和モ亦雙方同意ノ上ニ於テ之ヲ爲スヘシ 

第七條　兩締盟國ノ一方カ本協約中ニ規定スル場合ニ際シ他ノ一方ニ兵力的援助ヲ與フヘキ條件及該援助ノ實行方法ハ兩締盟國陸海軍當局者ニ於テ協定スヘク又該當局者ハ相互利害ノ問題ニ關シ相互ニ充分ニ且隔意ナク隨時協議スヘシ 

第八條　本協約ハ第六條ノ規定ト牴觸セサル限リ調印ノ日ヨリ直ニ實施シ十箇年間效力ヲ有ス右十箇年ノ終了ニ至ル十二箇月前ニ兩締盟國ノ孰レヨリモ本協約ヲ廢棄スルノ意思ヲ通告セサルトキハ本協約ハ兩締盟國一方カ廢棄ノ意思ヲ表示シタル當日ヨリ一箇年ノ終了ニ至ルマテ引續キ效力ヲ有ス然レトモ若シ右終了期日ニ至リ同盟國ノ一方カ現ニ交戰中ナルトキハ本同盟ハ講和ノ成立ニ至ルマテ當然繼續スヘシ 

右證據トシテ下名ハ各其ノ政府ノ委任ヲ受ケ本協約ニ記名調印スルモノナリ 

一千九百五年八月十二日倫敦ニ於テ本書二通ヲ作ル 

大不列顛國駐剳日本國皇帝陛下ノ特命全權公使 

　　　　　　　　　　林董　印 

大不列顛國皇帝陛下ノ外務大臣 

　　　　　　ランスダウン　印 

      外務省編「日本外交年表竝主要文書」上巻より

 

AGREEMENT OF ALLIANCE OF 1911. (Agreement of Alliance between Japan and Great Britain, 1911, Third Anglo-Japanese Alliance)

PREAMBLE. 

The Government of Japan and the Government of Great Britain, having in view the important changes which have taken place in the situation since the conclusion of the Anglo-Japanese Agreement of the 12th August, 1905, and believing that a revision of that Agreement responding to such changes would contribute to general stablity and repose, have agreed upon the following stipulations to replace the Agreement above mentioned, such stipulations having the same object as the said Agreement, namely: 

(a.) The consolidation and maintenance of the general peace in the regions of Eastern Asia and of India; 

(b.) The preservation of the common interests of all Powers in China by insuring the independence and the integrity of the Chinese Empire and the principle of equal opportunities for the commerce and industry of all nations in China; 

(c.) The maintenance of the territorial rights of the High Contracting Parties in the regions of Eastern Asia and of India, and the defence of their special interests in the said regions:-- 

ARTICLE 1.

It is agreed that whenever, in the opinion of either Japan or Great Britain, any of the rights and interests referred to in the preamble of this Agreement are in jeopardy, the two Governments will communicate with one another fully and frankly, and will consider in common the measures which should be taken to safeguard those menaced rights or interests. 

ARTICLE 2. 

If by reason of unprovoked attack or aggressive action, wherever arising, on the part of any Power or Powers, either High Contracting Party should be involved in war in defence of its territorial rights or special interests mentioned in the preamble of this Agreement, the other High Contracting Party will at once come to the assistance of its ally, and will conduct the war in common, and make peace in mutual agreement with it. 

ARTICLE 3. 

The High Contracting Parties agree that neither of them will, without consulting the other, enter into separate arrangements with another Power to the prejudice of the objects described in the preamble of this Agreement. 

ARTICLE 4. 

Should either High Contracting Party conclude a treaty of general arbitration with a third Power, it is agreed that nothing in this Agreement shall entail upon such Contracting Party an obligation to go to war with the Power with whom such treaty of arbitration is in force. 

ARTICLE 5. 

The conditions under which armed assistance shall be afforded by either Power to the other in the circumstances mentioned in the present Agreement, and the means by which such assistance is to be made available, will be arranged by the Naval and Military authorities of the High Contracting Parties, who will from time to time consult one another fully and freely upon all questions of mutual interest. 

ARTICLE 6. 

The present Agreement shall come into effect immediately after the date of its signature, and remain in force for ten years from that date. 

In case neither of the High Contracting Parties should have notified twelve months before the expiration of the said ten years the intention of terminating it, it shall remain binding until the expiration of one year from the day on which either of the High Contracting Parties shall have denounced it. But if, when the date fixed for its expiration arrives, either ally is actually engaged in war, the alliance shall, ipso facto, continue until peace is concluded. 

In faith whereof the Undersigned, duly authorized by their respective Governments, have signed this Agreement, and have affixed thereto their Seals. 

Done in duplicate at London, the 13th day of July, 1911. 

[L.S.] (Signed) TAKAAKI KATO, 

Ambassador Extraordinary and Plenipotentiary of His Majesty the Emperor of Japan at the Court of St. James. 

[L.S.] (Signed) E. GREY, 

His Britannic Majesty’s Principal Secretary of State for Foreign Affairs. 

 

 【日本語訳文】 

第三回日英同盟協約

明治四十四年七月十三日倫敦ニ於テ調印（英文） 

同年同月十五日官報彙報欄掲載 

（譯文） 

協約前文

日本國政府及大不列顛國政府ハ千九百五年八月十二日ノ日英協約締結以來事態ニ重大ナル變遷アリタルニ顧ミ該協約ヲ改訂シ以テ其ノ變遷ニ適應セシムルハ全局ノ静寧安固ニ資スヘキコトヲ信シ前記協約ニ代ハリ之ト同シク 

（イ）東亞及印度ノ地域ニ於ケル全局ノ平和ヲ確保スルコト 

（ロ）清帝國ノ獨立及領土保全竝清國ニ於ケル列國ノ商工業ニ對スル機會均等主義ヲ確實ニシ以テ清國ニ於ケル列國ノ共通利益ヲ維持スルコト 

（ハ）東亞及印度ノ地域ニ於ケル兩締盟國ノ領土權ヲ保持シ竝該地域ニ於ケル兩締盟國ノ特殊利益ヲ防護スルコト 

ヲ目的トスル左ノ條款ヲ約定セリ 

第一條　日本國又ハ大不列顛國ニ於テ本協約前文ニ記述セル權利及利益ノ中何レカ危殆ニ迫ルモノアルヲ認ムルトキハ兩國政府ハ相互ニ充分ニ且隔意ナク通告シ其ノ侵迫セラレタル權利又ハ利益ヲ擁護セムカ爲ニ執ルヘキ措置ヲ協同ニ考量スヘシ

第二條　兩締盟國ノ一方カ挑發スルコトナクシテ一國若ハ數國ヨリ攻撃ヲ受ケタルニ依リ又ハ一國若ハ數國ノ侵略的行動ニヨリ該締盟國ニ於テ本協約前文ニ記述セル其ノ領土權又ハ特殊利益ヲ防護セムカ爲交戰スルニ至リタル時ハ前記ノ攻撃又ハ侵略的行動カ何レノ地ニ於テ發生スルヲ問ハス他ノ一方ノ締盟國ハ直ニ來リテ其ノ同盟國ニ援助ヲ與へ協同戰鬪ニ當リ講和モ又雙方合意ノ上ニ於テ之ヲ爲スヘシ

第三條　兩締盟國ハ孰レモ他ノ一方ト協議ヲ經スシテ他國ト本協約前文ニ記述セル目的ヲ害スヘキ別約ヲ爲ササルヘキコトヲ約定ス 

第四條　兩締盟國ノ一方カ第三國ト總括的仲裁裁判條約ヲ締結シタル場合ニハ本協約ハ該仲裁裁判條約ノ有效ニ存續スル限右第三國ト交戰スルノ義務ヲ前記締盟國ニ負ハシムルコトナカルヘシ

第五條　兩締盟國ノ一方カ本協約中ニ規定スル場合ニ際シ他ノ一方ニ兵力的援助ヲ與フヘキ條件及該援助ノ實行方法ハ兩締盟國陸海軍當局者ニ於テ協定スヘク又該當局者ハ相互利害ノ問題ニ關シ相互ニ充分ニ且隔意ナク隨時協議スヘシ

第六條　本協約ハ調印ノ日ヨリ直ニ實施シ十年間效力ヲ有ス 

右十年ノ終了ニ至ル十二月前ニ兩締盟國ノ孰レヨリモ本協約ヲ廢棄スルノ意思ヲ通告セサルトキハ本協約ハ兩締盟國ノ一方カ廢棄ノ意思ヲ表示シタル當日ヨリ一年ノ終了ニ至ル迄引續キ效力ヲ有ス然レトモ若右終了期日ニ至リ同盟國ノ一方カ現ニ交戰中ナルトキハ本同盟ハ講和ノ成立ニ至ル迄當然繼續スヘシ 

右證據トシテ下名ハ各其ノ政府ノ委任ヲ受ケ本協約ニ署名調印ス 

一九一一年七月十三日倫敦ニ於テ本書二通ヲ作ル 

大不列顛國駐剳日本帝國皇帝陛下ノ特命全權大使 

　　　　　　　　　　　加藤高明　印 

大不列顛國皇帝陛下ノ外務大臣 

　　　　　　　　　イー、グレー　印 

       外務省編「日本外交年表竝主要文書」上巻より