As the initial landings progressed, the American forces on Okinawa found themselves between two seperate forces of Japanese troops. The largest was to the South, where Ushijima personally commanded the Shuri line, a collection of hills and ridges on the approach to Naha. In the North, General Chō had 40,000 men, which he was to use in a series of fighting retreats.
It was decided that the Army would go North, while the Marines would go south. General Geigers forces managed to overrun the first and least developed defensive line at the isthmus at Uruma, and continued North. The Army's progress was halted at the next lines, which were located at the neck of the Motobu peninsula and Higashi. These hill peninsulas were well suited to defense, and for two weeks almost no progress was made as the Japanese utilized their underground fortifications
Interestingly, despite both sides having used chemical weapons in prior actions, not a single gas weapon was deployed on either side. The Americans had phosgene in stock, but being unaware of the civilian evacuation of Okinawa, had decided to follow a no-first-use policy. The Japanese, under Soviet pressure to "keep the war clean" had not deployed their gas weapons either. The fighting was brutal enough without chemical weapons however, and neither side was eager to add gas to the mix.
The battle also marked the second tactical use of the B-29's. Inspired by the use of depth charges as improvised bombs at Warsaw, some of LeMay's staff had taken the idea even further. On April 12th, 300 B-29's made a low level pass over the Motobu line. Each of them carried three 2,000 pound bomb canisters that when reaching a preset altitude, split into hundreds of small bomblets. These in turn would detonate a mix of napalm gel at around 50 feet above ground height. This rendered the ground uninhabitable for several minutes, and suffocated many of the underground Japanese.
In the South the marines had a tougher time. The Shuri line was the most heavily developed fortification on the island. Ushijima had been very interested in the use of tunnels for the movement of troops, and so had put most of his effort into this. 100's of miles of tunnels snaked under the Shuri line, allowing entire brigates to move miles in good order. Some of the bravest marines would venture into these tunnels to keep up the attack, resulting in a three-dimensional battlefield that had multiple levels.
In one incident, an American forward command post was set up two miles from the front on the 15th. That night, an entire battalion of Japanese troops sprung out from a hidden tunnel. General Smitu, who was visiting the front, was wounded, and lost most of his staff. The entire affair was considered by many of all ranks to be a completely alien way to wage war, understood only by those who saw combat there.
In the air the Japanese still hadn't given up. While the kamikaze program had been shelved after promises of Russian fuel were made, the attacks made on the fleet around Okinawa were little better. 2,000 Japanese aircraft struck out at Okinawa, of which just 300 returned. Pilots were told to crash their plane if it was too damaged to return, leading to a belief that the Japanese were using suicide tactics. The picket destroyers suffered terribly, 15 Would be sunk in total. Additionally, two escort carriers were sunk, and two fleet carriers were damaged enough to withdraw. Morale was seriously threatened by these attacks, sailors and marines didn't have very different levels of stress during the campaign.
The struggle for Okinawa proved that Japanese morale was not broken, they would fight for every inch of their soil. It also resulted in grim forecasts for the expected invasion of mainland Japan, with military thinkers estimating it would take two years and 2 million casualties, to pacify the islands. With Europe boiling over, many began to wonder, Could the United States fight both the hammer and sickle, and the sword?
