"A Marine of the 1st Marine Division draws a bead on a Japanese sniper with his tommy-gun as his companion ducks for cover. The division is working to take Wana Ridge before the town of Shuri." S.Sgt. Walter F. Kleine, Okinawa, 1945. 127-N-123170. National Archives Identifier: 532559. June 1945 U.S. War Department

Military Tactics in the Battle of Okinawa

By Julian Landrove

Operation Iceberg was the code name for the American invasion of the Okinawa Island. This would be one of the bloodiest battles fought in the Pacific War, this battle would be vital in the determination of using the new atomic weapon on Japan. The Japanese saw Okinawa as the last line of defense. For the Japanese, holding the island was important because they knew that the Allies were going to use this island as a land base for strategic bombing and a harbor for the invasion of Japan. The Allies saw the island of Okinawa as a jumping off point for the inevitable invasion of the Japan itself. Okinawa could support the vast armada that would be needed to defeat Japan. The Okinawans would be the ones to pay a heavy toll because they would be caught between the two fighting forces. The tactics that were used by both the Japanese and American military in the battle of Okinawa were different; the Japanese took a defensive position, while the Americans and their Allies took an offensive position. All the while Okinawans tried to survived the war. The Japanese would use the terrain to slow the American advance, and the Japanese would attempt to bleed the Allied Naval forces. The American forces would conduct a massive artillery barrage followed by a sweeping maneuver to take the island. The Navy would defend the sky and support the American advance. The Okinawan men were forced to serve in the Japanese Army, while their loved ones tried to survive.

The Japanese had had over six months to prepare the defenses to repel the inevitable American invasion of Okinawa. The commander in charge of defending the island was Lieutenant Colonel Hiromichi Yahara. He reported to the commander of the 32^nd Army, General Mitsuru Ushijima which was the main garrison in Okinawa. The Chief of Staff was Isamu Cho. The Japanese 32^nd Army would adopt similar tactics used at Iwo Jima, which was to fight using underground tunnels and bunkers to fight the Americans. The Japanese army did not attack the beaches when the Americans came ashore. When the Imperial General Head Quarters (IGHQ) realized the immediate danger that Okinawa faced, they sent the 15^th Independent Mixed regiment to reinforce the 32^nd. The 9^th Infantry Division commanded by Field Marshall Shunroku Hata was also sent to support the garrison at Okinawa. The chain of command in Okinawa was different than the other locations, for example, in the book Hirohito’s War: The Pacific War, 1941-1945, Francis Pike explains “…the 32^nd army reported directly to Lieutenant General Sadamu Shimomura’s Western District army in Kyushu rather than to Imperial General HQ in Tokyo.”[1] Okinawa was to be given priority when it came to receiving supplies however, American Naval superiority would prevent many of the supplies from ever arriving to Okinawa.

The Japanese army was going to fight the Americans by using Okinawa as an airfield; they would also use tunnels to defend the island. In The Leavenworth Papers found on the Command and General Staff College website where it explains that the Japanese initially wanted to defend the island by air. “IGHQ expected the defense of Okinawa to be achieved mainly by air power and envisioned Okinawa as a gigantic air base.”[2] The Japanese believed that Okinawa could be held if it were turned into a giant airfield, and use air power to stop the invasion; however, the IGHQ did not realize that Japan had few planes and pilots to spare to achieve this goal. “…  Construction was slow. Moreover, because of U.S. submarine raiders, it was impossible for the Japanese to deliver the large quantities of fuel, ammunition, and antiaircraft guns needed to operate the bases. Even more seriously, the planes themselves were not available.”[3] This is an excellent example of how the Japanese were no longer in control of the Pacific Ocean. Further proof that the tide of the war was favoring America and its allies.

The Japanese army would use the same tactics as before in Iwo Jima back on the 19th of February 1945, which was to defend the island using a tunnel system to slow the American advance. The 32^nd army made tunnels and caves to defend the island against the Advancing American Army and Marines. “American air supremacy meant that every Japanese position had to be hardened and concealed, because air observation would bring devastating bombardment on any visible target.”[4] The Japanese 32^nd army was trying to bleed the Americans at Okinawa, buying time for the Homeland. “It would be lost, but a long battle of attrition would give time for the build-up of the mainland’s defenses.”[5] The Japanese army used the terrain against the Americans. “The 32^nd Army placed itself where it knew the U.S. Army must come, Okinawa, and it shrewdly chose terrain (1) that was strategically crucial for the Americans to capture for control of Nakagusuku Bay and Naha harbor, yet which also (2) was extremely favorable for the defender. (MacArthur had done the same on Bataan.) Having identified such terrain, the 32^nd Army thoroughly prepared it. Creating the cave environment was itself the 32^nd Army's greatest operational success.”[6] The caves and underground tactics were effective; however, it did not stop the defeat of the Japanese army in Okinawa by the American Military.

The American military knew that Okinawa would be vital as a jumping off point to the eventual invasion of Japan itself. Admiral Raymond Ames Spruance commanded Task Force 58. Admiral Spruance’s fleet also had British support. The British fleet was led by Vice-Admiral Sir Bernard Rawlings, his fleet “…consisted of 2 battleships, 4 fleet carriers, 4 cruisers plus HMNZS Gambia provided by New Zealand.”[7] Admiral Spruance’s fleet consisted of 1,500 ships the largest fleet ever assembled. Lieutenant General Simon Bolivar Buckner was the commander of ground forces that landed at Okinawa. As commander of the Tenth Army which was slotted to invade Okinawa and so the planning began to invade Okinawa.  The American Tenth Army consisted of four divisions: the 7^th, 27^th, 77^th, and 96^th Infantry Division and three Marine divisions: the 1^st, 2^nd, and 6^th Division. “In all, 183,000 soldiers (not including Seabees and support staff) were brought to the beaches of Okinawa…”[8] As General Buckner deployed his divisions on land after a weeklong bombardment, one of the longest bombardments of the campaign, Spruance and his Navy provided air support. Unlike the Marines in previous campaigns the Army was slow and methodical. This made the Navy prime targets of Kamikazes. Kamikaze means divine wind; these kamikazes were special suicide units. The kamikaze soldier or pilot would charge or crash their plane into the enemy. When the Americans landed on Hagushi beach the Marines pushed north while the Army pushed south. Resistance at first was minimal and sporadic in the North where the marines were pushing. However, in the south where the Army was advancing, resistance was fierce. The Japanese would hold their line for as long as possible and then withdraw into the cave and tunnel system to their new defensive lines and resist all over again. Progress was slow clearing the tunnels.

At sea the U.S. Navy was battling kamikaze attacks as well as the Japanese pilots. The “Japanese hurled no less than 11 major kamikaze operations, involving 1,465 planes, at the American fleet.”[9] The Japanese battleship Yamato was given orders to attack the American fleet, it was given enough fuel to make the attack. The American fleet attacked the Yamato and she was sunk. The Navy continued to support the Army with close air support. Bombing the area where it was needed. Massive bombings by the Navy helps the Army and Marines gain ground in Okinawa. The Navy also provides supplies for the ground forces on the island of Okinawa. The fighting on the island was fierce and costly in lives on both sides, even the Okinawans suffered from the battle of Okinawa.

The people of Okinawa were forced to endure the battle of Okinawa. Many of the men were forced to support the Japanese army. Some were in mixed units others supported the military. “…An estimated 150,000 Okinawans died during the battle…”[10] Many Okinawans still hold hostile feelings towards Japan. For example, the book Japan At War An Oral History by Cook and Cook which has an oral history by Ota Masahide an Okinawan who was a part of its defense. “…As a member of the Tekketsu Kinnotai, the ‘Blood and iron Student Corps.’”[11] Some of the Okinawa women tended to the Japanese wounded, many of them were left behind when the army withdrew. As the battle lines continue to shift the Okinawa people tried to move away from them. The Marines were pushing north and fought the Japanese on the northern part of the island, and the Army was advancing south the Japanese fight them there. The Okinawans the entire time caught in the middle. There was no safe place for them to go. If they went north there was fighting between the Marines and the Japanese, if they were in the south there was fighting there as well.

The battle of Okinawa began in April 1^st and ended in June 22^nd 1945. This battle was the last and bloodiest battle of the pacific war. The Japanese 32^nd Army had elaborate tunnel systems to defend against the invading American forces that split the island in half. The Marines took the north and the Army took the south. The American fleet was the largest in history which consisted of 1,500 ships to support the ground operations which consisted of seven divisions four from the Army and three from the Marines. There were 150,000 Okinawans killed during the battle of Okinawa. This battle was the turning point in the decision to drop the dumb. The fighting on Okinawa was fierce and it gave commanders an idea on how tenacious the Japanese people would fight if the invasion of Japan was carried out.