Trying to capture the island.
First, the U.S. wanted to fly onto the island to seize it so they could use it for prisoners. Also, they wanted to use it as a base for air operations. But, Japan knew that the allies were coming, so they got prepared. They had lines, and lines of defense.
Japan was ready for battle, they fought long and hard for their island. But soon, the U.S. started using their huge tanks, and pushing the Japanese forces backwards.