The Circle Plans – Japan’s method to achieve Hakkō ichiu


One year before December 7, 1941, the Japanese steel industry was coming to the realization that the enormous appetite from their military buildup was impossible to achieve. In the 1930’s, the United States was alarmed by the increase of Japan’s militant activity in Manchuria and elsewhere. After years of dormancy, the United States Navy was once again being rebuilt. Japan pulled out of the London Naval Treaty in 1934 and within a year invaded Northern China. The United States responded by diplomatic protest and the building of the USS Washington and North Carolina battleships.

The beginning of the war in Europe in 1939, military building on both sides of the Pacific increased. This huge building program stretched the Japanese to their limits in both shipbuilding and material supply. Key to both was the fact that Japan has no natural oil reserves and relied on other nations for the bulk of the precious commodity.

A strategy long advocated by the military and right wing members of Japans leadership was something called the Greater East Asia Co-Prosperity Sphere. This thinly veiled strategy of acquisition meant that Japan would take by force or deception any and all territory needed to provide the oil and all raw materials needed to self-sustain and extend her reach over China and her other neighbors.

Unable or unwilling to control the military, Japan’s political leaders sought greater security by establishing the “Greater East Asia Co-Prosperity Sphere” in August, 1940. In so doing they announced Japan’s intention to drive the Western imperialist nations from Asia. However, this Japanese-led project aimed to enhance Japan’s economic and material wealth so that it would not be dependent upon supplies from the West, and not to “liberate” the long-subject peoples of Asia. In fact, Japan would have to launch a campaign of military conquest and rule, and did not intend to pull out of China. At the same time, several pacts with Western nations only made Japan appear more of a threat to the United States. First, Japan signed the Tripartite Pact with Germany and Italy on September 27, 1940 and thereby linked the conflicts in Europe and Asia. This made China a potential ally in the global fight against fascism.

Milestones: 1937–1945 – Office of the Historian (

By December 1940, the Japanese industry reached a breaking point. The demands for more and more steel forced the leadership of the industry to resign and turn over their roles to the militants. This article comes from the December 7, 1940 edition of the Washington Evening Star Newspaper.

17 Iron Firm Officials Quit as Japan Seeks To Offset Embargo
Action Is Confession Demands for Greater Output Cannot Be Met
By A. T. STEELE, Chicago Dally News Foreign Correspondent.
TOKIO, Dec. 7. 1940

Another symptom of Japan’s strenuous struggle to neutralize the consequences of the American embargo came to the surface today with announcements of the mass resignation of all 17 directors of the Japan Iron Manufacturing Co., largest concern of its kind in the Japanese Empire.
This self-inflicted purge is expected to facilitate the government’s efforts to bring the entire iron and steel industry under more direct and coordinated state control. It was a confession of the inability of a collection of Japan’s outstanding industrial giants to meet the government’s demands for greater production of steel and iron in the face of the tightening American economic pressure. Hichishaburo Hirao, chairman of the company, issued a statement as follows:
“In addition to the prohibition on the export of scrap iron to Japan by the United States and Australia, and of pig iron by India, there is no guarantee but what we might find it very difficult to import iron ore, depending upon the future international situation.”

“Furthermore.” he added, “on account of the shortage of coal and transportation facilities, deterioration in the quality of iron ore, and shortage of labor and raw materials. It is very difficult to expect any marked increase in production under the present circumstances.

“On the other hand, the demand for iron and steel both for the military and otherwise is increasing in leaps and bounds, and the risk of a loss of balance in supply and demand is not entirely beyond possibility.

“In order to overcome these difficulties, but also to construct in East Asia a co-prosperity sphere parallel with the consummation of the China affair, as well as to prepare ourselves for the possible economic war that is likely to be created after the present European war, it will be necessary for us to build a powerful framework by completely reorganizing the steel and iron industry in this country on the basis of self-sustenance of industry among Japan, Manchuria and China.

Rapid Changes Cited. “However, we officers of the company were chosen in the days of the old order when such rapid changes as we are now witnessing were beyond our imagination. We, therefore, deemed it advisable to resign en bloc in order to clear the ground for a new national structure, and to await further instructions from the government.”
Hirao’s statement is an indicator how desperately Japan is rallying her ore supplies from South Pacific regions, especially British Malaya, as a means of making up for the deficiency caused by American embargoes. The production of her own mines in Japan and Manchukuo is still far short of her requirements, and the great storehouse of China, despite three years of Japanese occupation, is producing only 3 per cent of Japan’s total ore imports.

What was Japan Building with all of that Steel?

The Circle Plans

In response to the London Treaty of 1930, the Japanese started a series of naval construction programs or hoju keikaku (naval replenishment, or construction, plans), known unofficially as the maru keikaku (circle plans). Between 1930 and the outbreak of the Second World War there were four of these “Circle plans” which were drawn up in 1931, 1934, 1937, and 1939. The Circle One was plan approved in 1931, provided for the construction of 39 ships to be laid down between 1931 and 1934, centering on four of the new Mogami-class cruisers, and expansion of the Naval Air Service to 14 Air Groups.

However, plans for a second Circle plan were delayed by the Tomozuru capsizing and heavy typhoon damage to the Fourth fleet, when it was revealed that the basic designs of many Japanese warships were flawed due to poor construction techniques and instability caused by attempting to mount too much weaponry on too small a displacement hull. As a result, most of the naval budget in 1932–1933 was absorbed in modifications to rectify the issues with existing equipment.

In 1934, the Circle Two plan was approved, covering the construction of 48 new warships including the Tone-class cruisers and two carriers: Sōryū and Hiryū. The plan also continued the buildup in naval aircraft and authorized the creation of eight new Naval Air Groups. With Japan’s renunciation of naval treaties in December 1934, Circle Three plan was approved in 1937, its third major naval building program since 1930.

A six-year effort, it called for construction of new warships that were free from the old treaty restrictions, while concentrating on qualitative superiority to compensate for Japan’s quantitative deficiencies compared with the United States. While the core of Circle three was to be the construction of the two battleships Yamato and Musashi, it also called for building the two Shōkaku-class aircraft carrier, along with sixty-four other warships in other categories.

Circle Three also called for the rearming of the demilitarized battleship Hiei and the refitting of her sister ships, the Kongō, Haruna, and Kirishima. Also funded was upgrading of the four Mogami-class cruisers and the two Tone class cruisers, which were under construction, by replacing their 6-inch main batteries with 8-inch guns.

In aviation, Circle Three aimed at maintaining parity with American naval air power by adding 827 planes for allocation to fourteen planned land-based air groups, and increasing carrier aircraft by nearly 1,000. To accommodate the new land aircraft the plan called for several new airfields to be built or expanded; it also provided for a significant increase in the size of the navy’s production facilities for aircraft and aerial weapons.

In 1938, with the construction of Circle Three under way, the Japanese had begun to consider preparations for the next major expansion, which was scheduled for 1940. However, with the American second Vinson act in 1938, the Japanese accelerated the Circle Four six-year expansion program, which was approved in September 1939. Circle Four’s goal was doubling Japan’s naval air strength in just five years, delivering air superiority in East Asia and the western Pacific. It called for building of two Yamato-class battleships, a fleet carrier, six of a new class of planned escort carriers, six cruisers, twenty-two destroyers, and twenty-five submarines. The real emphasis, however, was on naval air power, in which the Japanese hoped to take the lead.

To achieve Asian air superiority Circle Four planned for the acquisition of 175 ship based aircraft and nearly 1,500 land based aircraft to be allocated to seventy-five new air groups. Upon completion of this expansion Japan would have 874 ship-based aircraft and 3,341 aircraft in 128 land based air groups, 65 of these being combat air groups and 63 training.

Because of the progression of ship building during this decade, Japan was ready to extend her reach into the countries that would for a while make up her Greater East Asia Co-Prosperity Sphere.

Hakkō ichiu

“all the world under one roof”) or Hakkō iu (八紘爲宇, Shinjitai: 八紘為宇) was a Japanese political slogan meaning the divine right of the Empire of Japan to “unify the eight corners of the world.” It was prominent from the Second Sino-Japanese War to World War II, popularized in a speech by Prime Minister of Japan Fumimaro Konoe on January 8, 1940.

Mister Mac

One thought on “The Circle Plans – Japan’s method to achieve Hakkō ichiu

  1. Thanks Mister Mac…I love history, even as a sonar systems engineer; never got this detail in my JHU electives or high school…Looking forward to more to come…

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