Part I
Assigned Tasks and Responsibilities

Immediately after the Japanese attack on 7 December, 1941, The Chief of Naval Operations, by dispatch to the Commander-in-Chief, Pacific and the Commander-in-Chief, Asiatic, directed that War Plan "WPL-6" be put into effect at once.1 Four days later, after Germany and Italy, by entering the war against the United States on the side of Japan, had established the array of nations anticipated in the U.S. Navy's "WPL-46", the Chief of Naval Operations in Alnav 150-41, directed that this later War Plan replace the earlier one.2

WPL 46, also known as "RAINBOW 5", was a detailed and comprehensive document. Based upon agreements made by the United States with Great Britain and with Canada, it had been prepared by joint U.S. Army and Navy planners in Washington and completed in May 1941. Under its provisions for a two-ocean war against the Axis Powers, the Commander-in-Chief, Pacific, was assigned a series of tasks which may be described as follows:3

  1. Protecting the sea communications of the Associated Powers (United States, British Commonwealth, Netherlands East Indies, China and others) by escort, covering and patrol operations as required by circumstances, and by destroying enemy raiding forces;

  2. Supporting the Army in the defense of the Hawaiian Coastal Frontier;

  3. Raiding enemy sea communications and forces;4

  4. Defending Samoa, Midway, Johnston, Palmyra and Wake;

  5. Protecting the territory of the Associated Powers in the Pacific Area was of 180°;

  6. Covering operations of Naval Coastal Frontier Forces and Canadian Naval Local Defense Forces;

  7. Establishing Fleet Control Zones and routing shipping of the Associated Powers within these Zones.

On 17 December, by agreement between the Secretary of the Navy and the Secretary of War, all Army Forces in the Hawaiian Coastal Frontier were placed under the Commander-in-Chief, Pacific, who thus, on the theory that there should be one Supreme Commander, assumed the responsibility for the defense of the Hawaiian Area.5

At this time, and for a few days longer, the Commander-in-Chief, Pacific, was, ex-officio, also Commander-in-Chief, United States Fleet. On 20 December, however, Admiral Ernest J. King was appointed to this senior Command, with Headquarters in Washington. Accordingly, when Admiral C.W. Nimitz relieved Vice Admiral Pye on 31 December, he assumed only the office of Commander-in-Chief, Pacific (CinCPac).6

On that same day, he received from Admiral King a dispatch directing that, in view of these changes in higher commands and in view of the early developments of the war, the tasks assigned to the Pacific Command be limited to two primary ones:

  1. Covering and holding the line Hawaii-Midway, and maintaining its communications with the West Coast.

  2. Maintaining communications between the West Coast and Australia, chiefly by covering, securing and holding the line Hawaii-Samoa, which should be extended to include Fiji at the earliest possible date.7

No further change in the status of CinCPac was made until 30 March 1942, when President Roosevelt approved his further designation as Commander-in-Chief, Pacific Ocean Areas. This designation, actually made known to Admiral Nimitz on 3 April, was based upon an agreement reached by the governments of the United States, the United Kingdom, Australia, New Zealand and the Netherlands, by which the Pacific Theater was made an Area for which the United States would have strategic responsibility.

Under the same agreement, the Pacific Theater was divided into (a) the Southwest Pacific, of which General Douglas MacArthur was to be Supreme Commander, and (b) the Pacific Ocean Areas, which included the North, Central and South Pacific and were to be commanded by Admiral Nimitz, with full authority over all the armed forces which the governments party to the agreement might send to those areas.8

The duties assigned to the Commander, Pacific Ocean Areas (CinCPac) by CominCh directive were outlined as follows:

  1. Hold the island positions between the United States and the Southwest Pacific Area necessary for the security of the line of communications between these regions and for supporting naval, air, and amphibious operations against Japanese forces.

  2. Support the operations of the forces in the Southwest Pacific Area.

  3. Contain Japanese forces within the Pacific Theater.

  4. Support the defense of the continent of North America.

  5. Protect the essential sea and air communications.

  6. Prepare for the execution of major amphibious offensives to be launched from the South Pacific Area and Southwest Pacific Area.9

In transmitting the above directive to CincPac-CincPoa, the Commander-in-Chief, U.S. Fleet noted: "You will consider (these tasks) . . . as supplementary to those outlined in my dispatch of 30 December."10

On 8 May 1942, Admiral Nimitz formally assumed command of all land, sea, and air forces in the Pacific Ocean Areas, except those assigned to the land defense of New Zealand, which had been excluded from the terms of the agreement; thus were established the Command relations which were to continue through all but the final four months of the Pacific War.11 A minor change in the boundary between the Pacific Ocean Areas and the Southwest Pacific Area was made on 1 August 1942 but, otherwise, the directive to CinCPoa and the tasks assigned him remained unchanged until the final reorganization of Pacific Commands, preparatory to the invasion of Japan in April 1945.12 (see below, Part II.)

Except for his being instructed to prepare for major amphibious operations and for initiation of unrestricted submarine warfare, CinCPoa's assigned tasks were primarily defensive. As will be seen in Part IV, specific directives on the planning and conduct of operations decided upon were to be sent him as occasion arose.

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Notes

1. CinCPac War Diary for December 1941; Entry under time of 1410/7 December.

2. Cited in CNO secret serial 014351, dated 11 December 1941.

3. WPL-46, paragraph 3212.

4. CNO dispatch cited in CinCPac War Diary for 18 December 1941.

5. CinCPac War Diary 18 December 1941; also CNO restricted serial 411229, dated 29 December 1941.

6. CinCPac War Diary, dated 20 December 1941.

7. CinCUS (Commander-in-Chief, U.S, Fleet) secret dispatch 301740, December 1941.

8. Establishment of the CinCPoa command was first announced to CinCPac in CominCh secret dispatches 031905 and 031922 of April 1942, which summarized the main provisions of the directive. The full text was transmitted with CominCh secret serial 00254, dated 3 April 1942. SecNav secret ltr. (SC)A16-3(28), dated 20 April 1942 effected general distribution to the Naval Establishment of the directives to CinCPoa and to the Supreme Commander, Southwest Pacific Area, embodying in them several minor changes of wording and an amplifying understanding with regard to the movement of Australian troops. This may therefore be considered the official text of the directive. (See Appendix I-1.)

9. "Directive to the Commander in Chief, Pacific Ocean Areas", Enclosure (B) to SecNav secret ltr. (SC)A16-3(28), dated 20 April 1942. (See Appendix I-2.)

10. CominCh secret serial 00254, dated 3 April 1942. See Appendix I-1.

11. CinCPac War Diary, dated 7 May 1942.

12. This change was included in the JCS directive fot he Solomons Operation: CominCh secret dispatch 022100, dated July 1942. It placed the western boundary of the area south of the equator at 159° East.


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