United States Indo-Pacific Bulletin on Okinawa, Site of the Last Major Battle of World War 2
This is a detailed and fascinating guide prepared by the US military in the lead-up to the invasion of Okinawa. This battle was one of the most destructive of the Pacific Theater, having more American deaths than any other campaign. Okinawa provided unique strategic advantages as a necessary stepping stone to the invasion of the Japanese homeland, and it became clear from early on in the war that any successful end to the war required Allied control of the island.
This booklet was produced in November of 1944, four months before the invasion would take place. This campaign required extensive coordination and planning due to the sheer enormity of troops and material needed to overrun the island. This booklet would have been used extensively by central command, captains, pilots, generals and others during the lead-up to the battle, fighting, and occupation. The booklet contains extensive notes regarding targets, assumed defensive tactics, navigational information, and much more. This source is important both for its breadth and specificity, being a work that would have been invaluable to anyone involved in the planning and execution of the battle, from high-level officers to pilots in bombing raids.
This bulletin was rated Confidential and an accompanying note instructs that the booklet should be destroyed when no longer of strategic value. No report of destruction was required. A last-minute update mentioning recent raids on Naha Town is printed on the title page.
Summary of Subject Bulletin
The work includes 127 pages of text, maps, and images, in addition to cover sheets and a distribution list. The contents of the work are briefly enumerated in the following paragraph.
The inside front cover includes a map of the western Pacific, with an inset of Okinawa Gunto. Page 1 provides an index. Pages 2-6 include a summary of Okinawa Gunto, the main island, and a map focusing on the installations on islands between Okinawa and Kyushu. Pages 7-34 include several maps and many areal photographs of the island, and includes sections entitled Climatology, Population, Health and Sanitation, Physical Geography, and Poisonous Snakes. Pages 35-64 discuss industry, transport, and navigational information regarding the islands, as well as including many detailed navigational charts. This concludes the background information on the island. The rest of the work focuses on target analysis, with a brief index and bibliography in the final pages of the booklet.
Distribution List
This is a loose two-sheet list of all the copies of this work and to whom they were sent out. This was issued by a Mr. R. Bacon, and includes a note stating that "when no longer of value [the bulletin] should be destroyed." Copies of this work were sent to dozens of army and marine battalions, as well as allied forces in England. Each Pacific cruiser, battleship, and destroyer also received a copy of this booklet. Interestingly, copies were sent to Naval Colleges perhaps so they could provide additional planning during the lead-up to the battle.
Background Briefing
This section is extensive and touches on many subjects of interest. Many of the problems which American soldiers would face on the island are recognized as potential issues. The poor drainage of the Yonabura-Naha-Itoman area is mentioned. Muddy conditions throughout the island, and especially in this area, would lead to conditions reminiscent of a World War I battle, with wheeled vehicles of limited use and the dead and dying strewn about. Other threats mentioned in the text failed to materialize: the deadly Habu snake (lithographed in the work), never became a prominent issue, and most GIs discarded the warm leggings they had been issued to prevent snakebites.
The bulletin is far from being solely focused on invasion, as it also includes reports on how best to occupy the island. Mentions of occupation appear throughout the work, providing extensive insights into the end-game planning of the US Army. This is particularly noticeable in the Population and Health And Sanitation sections. Specific proposals include retaining the local police, describing them as "paternal," and the extensive documentation regarding how best to deal with sewage. The subsequent occupation of Okinawa would mark the first occupation of an ethnically Japanese populace, and the US government wanted to be prepared for the fierce resistance it expected. One note in the work suggests that political crime on the island is high, perhaps a hopeful indicator that the occupation would not be as difficult as feared.
Target Information and Estimated Plan of Defense
Two sections at the end of the work explicitly deal with the tactics of an invasion. The first of these regards target information and attack recommendations. This section first spends spending forty-three pages detailing twenty target areas, and includes detailed maps, areal photos, and descriptions of both possible targets and civilian facilities. The final eleven pages go into detail regarding what a plan of attack on the island should look like. The section first details how to "absolutely neutralize" Japanese air capabilities, working from the premise that any attack must first seek to completely destroy all Japanese aircraft or all Japanese airfields. If the takeover of the island is to be quick, the latter possibility is said to be more appealing, and can be achieved best by heavy bombers. Should the fight for the island be prolonged, the former possibility is more desirable, and a different type of aircraft is needed.
This section continues with similar discussions regarding Military Defenses. These are to be taken out via a variety of means. How to best deal with anti-aircraft guns, pillboxes, fortified caves, minefields are all discussed. The famous Okinawan mausoleums are mentioned throughout the text as a possible threat or advantage. These large structures were recognized as strong points which could be used by Japanese or American soldiers, and were given much attention, with blueprints of their construction attached. During the war, they would be used occasionally as pillboxes, but more often as refuges for civilians looking for safety.
The final section of the work presents an estimated plan of defense. Intelligence is given as to Japanese forces in various parts of the island, as well as naval strength. The exact positions of battalions is suggested, as are their strengths and possible issuances.
Rarity
Approximately 1200 copies of this work were made. However, these were marked Confidential and meant to be destroyed once no longer of strategic value. Few appear to have survived, with none ever having been seen on the market before. The only institutional copy we have been able to locate is in the library of the USS North Carolina.
The United States Army and Marine Corps landed on Okinawa on April 1, 1945 as the specially-created 10th Army; the landing would be the largest amphibious assault in the Pacific Theater. The Battle of Okinawa, codenamed Operation Iceberg, lasted for 82 days after the landing, to June 1945 and claimed the lives of over 14,000 American and over 77,000 Japanese personnel. In addition, more than one hundred thousand Okinawans perished during and after the battle.
Okinawa was seen as the final island to overrun before the invasion of the Japanese homeland in Operation Downfall. This would be the closest American troops would get to the homeland prior to the dropping of the atomic bombs on Hiroshima and Nagasaki. Scholarship suggests that capture of the island was a motivating factor Japanese surrender, as it made a successful, though costly, invasion of the homeland inevitable.
The occupation of Okinawa would present unique challenges to the American army, as it represented the first time that the US would have to deal with a significant population that was (by most accounts) ethnically Japanese. Many Okinawans were initially very opposed to the Americans, and the Japanese army encouraged and forced mass suicides prior to the invasion. Despite this, the occupation was, for the most part harmonious. Okinawa remained under US military control until 1972, when it was returned to Japan.