Early in March the Japanese command on Okinawa, believing that Ie Shima could not be held for more than a few days, ordered that all airfields on the island be destroyed by the end of the month because of tactical requirements.{235} Thorough demolitions followed. The runways were ditched and blasted and the entire central area sown with mines, as defense against possible airborne attack. The enemy showed his usual resourcefulness; the mines included bombs rigged variously as pressure-detonating or controlled charges, wood and terra cotta antitank and antipersonnel charges, and fougasse mines made from drums of gasoline.
The Japanese defense plan was based on an elaborate attempt to trick the Americans. The defensive positions were concentrated in and around the town and the Pinnacle because the terrain and the structures there were well adapted for fortification. Consequently, the central east sector of Ie became by far the strongest area; the western part of the island was merely outposted and mined. Furthermore, the best landing beaches were near the southeast end of the island and were commanded by the strong positions in the Ie-Iegusugu area. The Japanese hoped to lure the invaders in over these exposed southeastern beaches and then to destroy them by intense fire from hundreds of concealed positions in the Pinnacle and the town of Ie. They tried to deceive the Americans into thinking that the good southeastern beaches were not defended while the poorer beaches were heavily defended; if the ruse succeeded and the Americans landed on the southeast, the Japanese could exact a heavy price. Consequently, when American reconnaissance parties operated off the southeastern beaches, they were not fired on and could see no indication of the enemy; one American actually strolled along the beach without drawing fire. Pilots flying 100 feet over the area saw no sign of activity. But on the less desirable southern and southwestern beaches the situation was reversed. Here, in accordance with the Japanese stratagem, beach reconnaissance parties drew considerable small-arms fire from the shore.{236}
Map No. 19: Landings on Ie Shima
The ruse failed. The 77th Division staff relied on photo interpretation and map study, which provided an accurate means of plotting the development of defensive installations on Ie. After studying photo intelligence reports of 1 March, the G-2 of the 77th stated on 15 March that the nature of the defenses on Ie made a landing on the southeast undesirable, since such a landing would encounter maximum initial resistance:
“Therefore, from a consideration of both terrain and enemy action, a landing over the beaches on the southwest end of the island should meet with the greatest initial success. An attack from the west enters the back door of the defensive organization east of the airport. However, the capture of key terrain and the best beaches for bringing in heavy equipment will be delayed.”{237}
This analysis set the pattern of the attack. General Bruce, in a field order issued 12 April 1945, ordered the 305th Regimental Combat Team (RCT) to land on Red 1 and 2 on the south coast of Ie Shima on 16 April and the 306th RCT to invade Ie simultaneously over Green Beach at the southwest end of the island. While the 305th advanced eastward to seize additional landing beaches, the 306th was to swing around on the 305th's left (north) flank and overrun the airfield. Together the two regiments would reduce the strong points at the eastern end of the island. The troops would be supported by the 105-mm. howitzers of the 305th and 902d Field Artillery Battalions and by the 155-mm. guns of the 306th, which on the day before the landing were to be emplaced on Minna Shima, a sand islet four miles south of Ie.{238} (See Map No. 19.)
This plan was adopted over the objections of supply officers of the 77th, who pointed out that reef conditions off the selected beaches would prevent the use of landing craft except for a short time at high tide. The surfaces of the wide coral reef offshore were so rough and broken that nothing but LVT's and DUKW's could negotiate them.{239} It was planned, however, to unload only a minimum of supplies over these beaches and to unload the heavy equipment over the more desirable beaches farther east-Red 3 and 4-once they had been secured by the 305th RCT.{240}
Although the Japanese failed to lure the invaders onto the best-defended beaches, they did succeed, through excellent camouflage, in concealing their strength on Ie. During early April the 77th received a series of reports from air observers which indicated that Ie was almost deserted. On 6 April General Bruce, explaining his plan to General Buckner, wrote as follows:
“. . . original estimate of enemy is considerably reduced. It is planned to take entire division to target area; secure island quickly with minimum forces, less heavy equipment.
“. . . This plan places sufficient forces in immediate target to quickly and unquestionably complete mission with minimum casualties.{241}”
Actually, the entire division was not available to General Bruce. The 2d Battalion of the 305th Infantry was garrisoning the Kerama Islands. The 307th RCT was being held in readiness by Tenth Army to feint a landing on the southern beaches of Okinawa in connection with an attack planned for 19 April. All but the 1st BLT of the 307th, however, was made available to General Bruce during the operation. The 77th had suffered some casualties in the Keramas, but the number was doubled by Kamikaze attacks on division shipping during the early part of April. On 2 April, during a night retirement, the 77th Division convoy was caught twelve miles south of Kerama Retto by a flight of Japanese suicide planes which attacked from the clouds. Four ships were crash-dived before fighters and antiaircraft drove off the enemy craft.{242}
In preparation for the landings, units of the Fifth Fleet bombarded Ie Shima intermittently from 25 March through 16 April. Systematic bombardment of the island began on 13 April when the battleship Texas, two cruisers, and four destroyers fired on targets throughout the island, concentrating on the strong points in the east. That evening six rocket LSM's began a night interdiction and harassing patrol of Ie, firing rockets and 40-mm. shells and executing illuminating missions. A similar schedule was followed on the 14th; on the 15th the daylight bombardment of Ie was canceled to prepare for other required dispositions of the fire support ships.{243}
During the first ten days of April, Navy fighters and light bombers attacked caves, buildings, and installations on Ie Shima. After a spell of bad weather from 10 to 12 April, the air strikes were intensified. During the period 13-15 April 54 strikes comprising 292 sorties were flown; 830 rockets, 35 tons of bombs, and full loads of .50-caliber ammunition struck all targets that could be located by observation and by study of aerial photographs. All remaining emplacements around Ie were neutralized and two aircraft found on the field were destroyed.
ROCKETS OVER IE SHIMA, fired by a Navy airplane toward the Pinnacle. Beyond, to the south, are Ie and Government House, almost obscured by smoke of preinvasion softening-up. Dark area (upper right) is nose of plane
Under the cover afforded by these air and surface strikes, Navy underwater demolition teams conducted daylight reconnaissance of all beaches on Ie during 13 and 14 April. Except for light and inaccurate enemy fire on the western beaches, the swimmers met no opposition. The teams provided the earliest firsthand information on Ie; although their observations were made from the water line, their reports on beaches and terrain immediately inland proved to be accurate.
On the night of 12-13 April the Amphibious Reconnaissance Battalion of the Fleet Marine Force, Pacific, landed on Minna Island and secured it without resistance. On 15 April, the 305th, 902d, and 306th Field Artillery Battalions went into position on Minna to support the Ie operations. Each battalion quickly registered on base points and check points established on the target. Three cub planes, operating from a field constructed within a few hours after the landing, conducted registration missions for the battalions. There were no preparatory or neutralizing fires, however, until the attack began on the following day.{244}
It had been the enemy's original plan to cover Ie Shima with his own artillery on Okinawa. During the operations on Motobu the marines overran a battery of two 150-mm guns, complete with prime movers and ammunition, near the west coast of the peninsula. The guns were in a steep draw which opened directly toward Ie Shima. They were to be fired from the mouths of caves and to be pulled back when not in use. Late in March, General Ushijima had ordered the naval detachment in charge of the guns to prevent American use of the airfields on Ie; the two guns completely covered the island.{245} By the time of the invasion of Ie, the situation had been neatly reversed; the enemy had lost his guns, and Ie Shima was exposed to American medium and heavy land artillery as well as to the powerful guns of the Pacific Fleet.
Two battleships, four cruisers, and seven destroyers of the Fifth Fleet opened up a heavy bombardment of Ie Shima at dawn of 16 April. LCI's swept the landing beaches with rockets and mortar shells. Thousands of rounds of 40-mm., 20-mm., and .50-caliber ammunition arched into the beaches from support craft and from guide boats escorting the first landing waves. Planes bombed and rocketed the island and dropped tanks of napalm on and behind the beaches. Billowing clouds of smoke and dust rose from the flaming napalm, exploding ammunition dumps, and burning gasoline stores. Within a few minutes Ie Shima was blacked out. Puffs of white smoke against the gray pall over the island showed where the rocket and mortar ships were preparing the beaches. A Japanese soldier wrote in his diary: "After fierce air and naval bombardment, the enemy began his landing in front of the 4th Company, using amphibian tractors. Their fire power is so great we dared not show our heads."{246}
Debarkation of the landing craft from the LST's went smoothly. By 0650 boat waves were forming in the assembly area. Soon afterward amphibian tanks, followed by waves of amphibian tractors, roared toward the landing beaches from the line of departure 3,600 yards offshore. The weather was clear and bright and the sea was calm. The tanks and tractors moved past the cruisers, destroyers, and LCI's to the smoking beaches. As the first waves neared the shore, support fire was directed inland.{247}
At 0758—two minutes ahead of schedule—the forward elements of the 1st BLT of the 305th landed on the southern coast of Ie directly south of the airfield. Three minutes later the 3d BLT of the 305th started landing on a separate beach 600 yards to the left (west). The troops pushed rapidly inland over high dunes. On reaching a road which ran along high ground 400 yards north of the beaches, the 1st Battalion swung east. From this high ground to the town of Ie there were extensive mine fields which, although hurriedly laid and crudely camouflaged, slowed the movement of amphibian tanks and self-propelled guns. The 3d BLT moved inland and then swung east toward Ie, its left flank passing just south of the easternmost air strip.
At 0807 the first waves of the 306th RCT landed on a 600-yard-wide beach at the southwest end of Ie, with the 1st BLT on the left (north). Within three hours the assault battalions advanced 2,000 yards inland to the western edges of the airfield. The 3d BLT of the 306th completed its landing at 1015 and, as the reserve battalion, patrolled the western end of the island. After mopping up small groups of Japanese in caves and entrenchments, the 3d BLT resumed its advance to the east, echeloned to the left rear of the 1st BLT of the 306th.
INVASION OF IE SHIMA was well prepared but met considerable opposition. Assault boats (above) approach the island as supporting shell fire is lifted from the beaches and moved inland. Eight hundred yards inland from Red Beach 2 were these cave positions (below), around which the 305th RCT, 77th Division, was engaged in an infantry-demolition fight until nightfall of 16 April.