Imperial Defense Policy (帝国国防方針)

Imperial Defense Policy was the basic guidelines for military strategy in the Empire of Japan.


The Imperial Defense Policy was military secret documents in which the basic strategy of national defense was written. The guidelines were composed of three parts; the Imperial Defense Policy, the military force for national defense, and the guidelines for imperial tactics. In the first part, the policies for national defense outlined the national goal and strategy, objective and policy for national defense, imagined enemy, situational judgment, and required armaments.

In the second part, the numerical targets such as the number of divisions and warships were set as the specific goal of the required military force and military policy. In the third part, the outline of individual operation plans for a Japanese military doctrine and the imagined enemy was stated.

The Imperial Japanese Army (IJA) presented a plan to formulate a comprehensive national defense policy for Army-Navy operations, and it was approved by the Emperor Meiji on April 4, 1904, and was revised in accordance with changes in the international situation, etc. However, in fact, the situation never changed in which the Japanese Army considered Russia as the imagined enemy and the Imperial Japanese Navy considered the United States of America as the imagined enemy, and therefore the original intentions to unify the ideas of national defense was achieved imperfectly.


Following the revision of the Anglo-Japanese Alliance in August, 1905, just after the end of the Russo-Japanese War, it was the beginning of the Imperial Defense Policy that Aritomo YAMAGATA reviewed the action policy of the Japanese army if the war between Great Britain and the Russian Empire should start. The possibility of the war was lost due to the conclusion of the Triple Entente and the Russo-Japanese Agreement, but Yamagata who regarded it as the golden opportunity to break through the situation of 'Navy is a major, Army is a minor' in the longtime national defense, aimed at the final draft of the formulation. It was the draft by Giichi TANAKA who was a Lieutenant Colonel of the army based on the Yamagata's draft. The navy side also drew up a similar plan against this, and the Army and Navy submitted the plans.

Considering the imagined enemies as Russia, the United States of America, German, and France, the army demanded 25 divisions in peace time and 50 divisions in wartime, and the navy demanded the deployment of 8 battleships and 8 armor-clad cruisers. Then Prime Minister Kinmochi SAIONJI was permitted only to give advice on the policy for national defense and to access the required military force, and for the tactics manifesto, his involvement was blocked on the strength of the supreme command. To exclude the prime minister from the final decisions on the policy for national defense meant that the implementation of the policy could not be guaranteed by the government and, in fact, adding two more divisions was rejected due to the financial problem.

With the firm commitment to enlarge the military force, it became a problem that the situation of the imagined enemies did not reflect the circumstances surrounding Japan.
(In the revision in 1918, the assumption of Germany's victory and the military alliance between Germany and Russia in the First World War brought the problem to put the policy back on the drawing board due to the Russia Revolution.)
Therefore, in the revision in 1918 and in 1923, the military submitted the policy to the Cabinet and requested the agreement, and in the revision in 1936, it showed willingness to compromise with the government to formulate a coherent imagined enemy based on the opinion from the Minister for Foreign Affairs.


The Imperial Defense Policy was revised in 1918, in 1923, and in 1936, but there were no significant changes. However, the order of the imagined enemies had been changed from Russia, the United States of America, and China to the United States, China, and the Soviet Union, and in the third revision, it was changed to the United States, the Soviet Union, Great Britain, and China. The Guidelines for Imperial tactics' and 'the Annual operation plan' were drawn up based on the Imperial Defense Policy.

Imperial Defense Policy in 1907

The policy for national defense formulated on April 4, 1907, stated two points; to firstly expand the sovereign right as the national goal based on a national virtue which was the opening of Japan, and to promote national interests and people's welfare.

The national strategy based on the national goal was specified to protect and expand the interests which were implanted in Manchuria and the Korean Empire and the development of resources of a nation which was extending to the Southeast Asia and China. Therefore, the policy for national defense stated that the national defense by the Imperial Army would take the offensive against countries that attempted to violate Japan's national strategy in East Asia, and clearly rejected the defense-only policy due to the establishment of interests in Manchuria and Korea.

Imperial Defense Policy in 1918

The official text of the policy for the national defense on June 29, 1918, was incinerated at the end of the war, and the contents of the policy were conjectured with the relevant documents. Since there was no great change in the national goals which were the opening of Japan and the promotion of national interests and people's welfare, and in the national strategy which was the invasion of China and Southeast Asian in the previous policy, the policy was not significantly changed.

However, the First World War influenced the Japanese military doctrine and Japan recognized the need for all-out war system.

Imperial Defense Policy in 1923

The policies described in the revision of February 28, 1923 were prioritized according to the following order: national virtue, national goal, national strategy, and policy for national defense. Although consistency in the political strategies was emphasized, the national virtue and the national strategy were omitted, and they were summarized as the principal doctrine for national defense.

The primordial doctrine was described only the guarantee of independence, the protection of national interests and sovereign right, the national development, and the promotion of people's welfare as the national goal in principle, and there was no specific definition for the national strategy as before. As the military doctrine it emphasized the offensive of short-term operation with consideration of all-out war.

The military doctrine of the offensive operations was stated which were to beware of foreign countries where conflicts occurred after avoiding international isolation, to endeavor to have an advantage in the war with a close alliance while preventing the enemy countries from uniting, and to defeat the enemies in a foreign country and bring the war a rapid end.

Imperial Defense Policy in 1936

In the revision on June 3, 1936, it was constructed from the previous revised version; the national virtue, national goal, and national strategy were summarized as the primordial doctrine for the national defense. The primordial doctrine for the national defense was the principal which was to enhance the national authority and to promote economic prosperity.

And the policy for national defense stated to ensure national development in diplomacy and to set first-strike principal and short-term operation in a military contingency as the military doctrine. Preparation for military force in peace time which was necessary for the short-term operation was emphasized with consideration of long-drawn-out and all-out war.

[Original Japanese]