With the fall of Saipan in July 1944 (the 19th year of the Showa Era) came the fall of the “Absolute National Defense Zone”—the selected areas and locations which Japan had deemed necessary for defending the Empire. The Pacific War reached a critical situation two years and seven months after its opening in December 1941.
Everything indicated that defeat was certain, but Japan attempted to fight a decisive battle with the United States, which led to the Battle of Okinawa. Why did Japan force so many Okinawans to sacrifice themselves, and what were the mistakes the government and the Imperial Headquarters made in their strategy?
Desperation leading to battle
The Army and Navy Departments of the Imperial Headquarters decided in the summer of 1944, after losing the Mariana Islands—Saipan, Tinian and Guam—to fight a battle on Japanese soil, concluding, “There is no other time but now to wage a decisive battle from a war-commanding standpoint.” Following the fall of the “Absolute National Defense Zone,” the military headquarters drew up a battle plan called “Shogo Operation,” as the Chinese character “sho”means “winning a battle.”
The areas designated for the operation were the Philippines, the battle plan for which was called Sho Number One, Taiwan and the Nansei Islands including Okinawa, Sho Number Two, and the Japanese mainland, Sho Number Three. The plan was to engage U.S. forces in the three areas. What process was required to establish new war-leadership principles or “Senso Shido Taiko” to carry out the Shogo Operation?
Prime Minister Hideki Tojo took responsibility for the fall of Saipan and felt forced to resign. Kuniaki Koiso succeeded him, forming a new Cabinet on July 22, 1944. Immediately after the Cabinet formation, Koiso said, “I will practice every measure to successfully conclude the war.”
What he had in mind was to push back the U.S. forces for once, which would possibly lead to a peace treaty between the two countries.
On August 4, in an effort to strengthen his authority over the conduct of war, Koiso established the Imperial Supreme War Council which comprised the prime minister, foreign minister, war minister, navy minister, chief of the army general staff and chief of the naval general staff. The new council was given a green light at the conference but it was just a continuation—rather than an improvement—of the Imperial Headquarters-Government Liaison Conference. The council adopted Senso Shido Taiko (War Leadership Principles).
The Army General Staff’s Twentieth Group in charge of war coordination, headed by Colonel Sako Tanemura, was responsible for drafting the new War Leadership Principles to be adopted by the Imperial Supreme War Council.
The War Coordination Group saw the situation as extremely grave. According to its draft, the war situation was critical—Japan could end up in the worst possible scenario; there was no prospect of increasing military capability for achieving war aims and repelling the U.S. forces. Since sustaining the livelihood of the Japanese people would become difficult from the next year onward as the Group was not confident of victory in any future battle.
The difference in strength between Japanese and U.S. naval and air forces continued to grow. The Imperial Japanese Army and Navy had about 3,000 aircraft while U.S. industry was capable of producing 10,000 a month. The U.S. and British naval strength included 17 aircraft carriers, 46 light aircraft carriers and 63 battleships and battle cruisers. Meanwhile, the Combined Fleet had seven aircraft carriers and 15 battleships and battle cruisers.
However, Koiso declared at the Imperial Supreme War Council meeting on August 19, “We will make every effort to wage a decisive battle and overcome this critical situation.”
Echoing him, Chief of the Army General Staff Yoshijiro Umezu said: “We’ll change the war situation and show the enemy the capability of our Army and Navy.” Foreign Minister Mamoru Shigemitsu, War Minister Hajime Sugiyama, Navy Minister Mitsumasa Yonai and Chief of the Naval General Staff Koshiro Oikawa were present at the meeting. Sugiyama and Yonai said they all should believe in victory and make an effort to finish the war. The meeting ended after Emperor Showa said: “We have made a good policy, but we have to make sure it will be carried out correctly. Make every effort to practice the principles thoroughly.”
The Army General Staff and the Naval General Staff had already drawn up the Shogo Operation plan. With the Council’s approval of the new war-leadership policy, the Imperial Headquarters started working on preparations for battle. However, the Army and Navy were defeated on Leyte Island in the Philippines in October 1944. U.S. forces landed on Luzon in January 1945 and retook Manila. Thus battle plan Sho Number One had failed, which left no other choice for the Japanese headquarters but to pursue the final battles in Okinawa and the mainland. So what plan did the Imperial Headquarters have for the Battle of Okinawa?
The Thirty-second Army in charge of defending Okinawa was formed in March 1944. After the fall of the Mariana Islands in July, the Imperial Headquarters hastily called back three divisions from Manchuria and other places. Divisions 9, 24 and 62 were incorporated into the Thirty-second Army. Headquarters ordered the Thirty-second Army to build airdromes. Most of Japan’s fighters had been destroyed in the naval battle off Marianas in June, which greatly diminished the strength of Japan’s airpower. However, the headquarters was obsessed with the idea of crushing U.S. forces from the air before they landed on Okinawa, calling Okinawa an “unsinkable aircraft carrier.” The Thirty-second Army suspended its work on taking positions for over a month and instead worked on building 15 airdromes in the Nansei Islands.
Then, the Imperial Headquarters tried to move the Ninth Division to Taiwan in November. Commander of the Thirty-second Army Mitsuru Ushijima strongly opposed this, saying, “If it is imperative that we defend Okinawa Island, extracting a division from the Army is not an option.”
In December, Shuichi Miyazaki became chief of operations at the Imperial Headquarters’ Army Department. He pressed on with the plan to move the Ninth Division to Taiwan, saying: “Discussing troop strength in Okinawa is nothing but a defeating attitude in giving up the Philippines. The Ninth Division will be moved by all means.” At the same time, Miyazaki’s counterpart in the headquarters’ Navy Department, Sadatoshi Tomioka, insisted: “U.S. forces are likely to attack Okinawa next. Okinawa will be the place for a showdown.”
Indeed, the United States had made a decision in early October to invade Okinawa. It considered the Okinawa invasion the most important of all, as securing the command of the seas and the air around Japan would allow it to strike at the heart of Japan. The Imperial Headquarters’ Army Department had made an utterly erroneous prediction. Miyazaki remained stubborn, rejecting the Thirty-second Army’s request to add another division to Okinawa. He said, “The Army in the field should solve the problem.”
In January 1945 when Umezu decided to dispatch the (mainland) Eighty-fourth Division from Himeji, Hyogo Prefecture, to Okinawa, Miyazaki opposed, saying: “We should not send too many troops to remote islands where naval transportation is insecure. I refuse to understand why we have to watch valuable defense forces be sunk in the ocean.”
Hearing the opposition, Umezu said, “You do whatever you like,” and reversed his decision to send the troops. Miyazaki rejected the idea of strengthening the troops in Okinawa because he felt preparations for defending the mainland should be prioritized, guessing that U.S. forces would not come to the mainland until that autumn, or later. A possible decisive battle on the mainland was all Miyazaki had in mind.
The Outline for the Navy Operation Plan, finalized on January 20, stated that its purpose was to “secure the Imperial land, especially the Empire of Japan’s mainland,” and said, “the Ogasawara Islands, Okinawa Island and the Nansei Islands located to the south of Okinawa are the front line in accomplishing a so-called deep battle operation to defend the Imperial land.” But for the Imperial Headquarters and the government, Okinawa was not recognized as part of the mainland of Japan.
When interrogated by the General Headquarters of the Allied Powers after the war, Takushiro Hattori, who was chief of the Operation Section of the Imperial Headquarters’ Army Department, admitted the plan was to have a drawn-out battle on Okinawa to let U.S. soldiers bleed so that Japan would win a decisive battle on the mainland.
Thus Okinawa was to be sacrificed to buy time until the preparations to defend the mainland were ready.