War in the Pacific Cultural Resources Inventory

PART 2a

American Strategy to Liberate Guam 1944

The United States military realized that the three major islands of the Mañana Islands, Guam, Saipan, and Tinian, were necessary for B-29 airbases. From these islands, the aircraft could complete round trip air raids to Japan. Possession of these islands would also sever the Japanese aircraft ferry route to Chuuk, Palau and Woleai. In addition, Guam's Apra Harbor would serve United States interests as a submarine refueling base, a good anchorage for an advance naval base, and a major supply center for the U.S. military forces. The justification to recapture the former United States territory was also driven by the need to liberate the Chamorros.

Original plans called for the assault on Guam to begin on June 18, 1944. However, U.S. forces landed on Saipan on June 15th, known as D-Day. They secured the airfields on June 18th, but did not secure the whole island until July 9th, 1944. The unexpected strength of the Japanese defense and the approach of the Japanese Combined Fleet from the Philippines towards the Mariana Islands lead to the postponement of the attack on Guam.

Admiral Chester W. Nimitz, Commander In Chief of U.S. Pacific Fleet, decided upon July 21 as the invasion day instead of the scheduled date of June 18th. The Island of Guam was one of the U.S. military's strategic target islands in the Pacific Theater of War during World War II. The code name FORAGER was assigned to the recapture and liberation of Saipan, Tinian, and Guam. The code name for the recapture of Guam was STEVEDORE.

In April of 1944, U.S. submarines and long-range seaplanes began photographing and conducting reconnaissance on Guam. During the United States forty-three year presence on Guam, little to no mapping or physical information was recorded. Only poor quality aerial photographs, previous island stationed personnel, and a few Chamorros who served in the U.S. Navy were the source of information to chart road systems and topography. These sources were used to produce new maps for strategic planning of the invasion. The roads were built by the Seabees (U.S. Naval Construction Battalions).

The natural features and built infrastructure of the island were never recorded. Once the Japanese overtook and occupied the island, Navy intelligence had to rely on personnel who had previously been stationed on Guam and Chamorros who were serving in the U.S. Military for mapping field conditions. "Minor roads constructed by the enemy were not shown and in some cases there were errors in roads constructed by the U.S. Military prior to the occupation of the island by the Japanese" (Gailey 1988:60). Despite the limited knowledge of roads prior to July 21, 1944 and Japanese landmines placed along them, American troops still made use of existing roads. Landmines were often obvious and easy to deactivate. As soon as the landing beaches were secure by American troops, numerous bulldozers and tanks were brought ashore to expand the network of existing roads. Historic photographs show new roads being cut from the landing beach up the hills to expedite the transport of ammunition and supplies to advancing troops.

In May, American B-29 bombers began to bomb Saipan and Guam. On June 11-12, the Fast Carrier Task Force 58 destroyed 150 Japanese planes in an air assault. From this point on, the United States dominated the skies and seas of the Mariana Islands (Rogers 1995:176). On June 18-20, the American fleet turned to approach the oncoming Japanese fleet head-on. The United States lost 130 aircraft and the Japanese lost 3 aircraft carriers and 476 planes in the Battle of the Philippine Sea known as the "Great Marianas Turkey Shoot". This left Lieutenant General Takeshi Takashina commanding the General 29th Division and Japanese forces on Guam without backup to face the oncoming invasion (Rogers 1995:176).

Three weeks prior to landing, extensive air raids were carried out in an attempt to secure Asan and Agat beaches, where American Armed forces were to begin their initial assault. The offensive strategy, now apparent to the Japanese, was to land on Asan and Agat beaches and unite these forces by capturing the Orote Peninsula. The Orote Peninsula was edged with 200-foot cliffs overlooking the two beaches. It also contained the only functional airfield, crucial in order to secure and cut off Japanese supplies, and to bring in additional American supplies.

A critical error occurred when both the initial U.S. Military reconnaissance team and bombers neglected to identify five coral rock outcrops along Asan and Agat beaches. They were mistaken for sand dunes covered in vegetation and were therefore not targeted by the bombings. Japanese pillboxes and bunkers were clustered in these five coral outcrops: Apaca Point, Ga'an Point, Bangi Point (on Agat Beach) and Adelup Point and Asan Point (on Asan Beach). The structures survived the intensive pre-invasion bombing, and became Japanese strongholds. These strongholds had a significant influence on the outcome of the battles fought on the Asan and Agat beaches and they remain today as reminders of these events.

The U.S. Marines, responsible for combat, were to land on Asan and Agat beaches. Both beaches were divided up into four sections. Asan Beach, between Asan and Adelup points included (west-east) Blue, Green, Red 2, and Red 1 sections. The 3rd Marine division (Major General Allen H. Turnage, and Colonel W. Carvel Hall) would land on Asan Beach closest to Adelup point (red beach 1 and 2) and move to secure Chorito Cliff and Adelup Point. On Asan Beach closest to Asan Point, the 9th (Colonel Edward A. Craig) would land on blue beach and seize and hold the low ridges while the 21st Marines, commanded by Colonel Arthur H. Butler, would land on central green beach and drive inland and clear a way for expanding the beachhead (Roger 1995:182, Lodge 1998:38) (see invasion strategy map).

Agat Beach, often referred to as the Southern Assault Beach, was also divided into four units: (north-south) Yellow 1, Yellow 2, White 1, and White 2. Lieutenant Colonel Alan Shapley' s 4th Marines were to land far right, establish the beachhead and protect the brigade. The 305th RCT (from the 77th Army Infantry Division) were the brigade floating reserve commanded by Colonel Vincent J. Tanzola. Colonel Merlin F. Schneider's 22nd Marines would land far left, secure Agat Village and drive north towards the Orote peninsula. Beaches Yellow and White were targets of the First Provisional Marine Brigade led by Brigadier General Lemuel C. Shepherd with a back up of the 77th Army Infantry under Major General Andrew D. Bruce. Together these two forces made up the III Amphibious Corps. Once ashore, they would be under the command of Major General Roy S. Geiger of the U.S. Marine Corps (Rogers 1995:182, Lodge 1998:47-8).

Both units were to advance inland and establish the Force Beachhead Line (FBL) along the ridges from Fonte Plateau, Mounts Alutom, Tenjo and Alifan (see invasion strategy map). The securing of the FBL would secure the American position along the entire division front. After securing the FBL, forces were to converge and isolate the Orote Peninsula and the airfield upon the peninsula, and then continue to liberate the remainder of the island.

The Japanese had the advantage of the natural topography, which lent itself to defending the beaches and Orote Peninsula. The Americans had the advantage of three-to-one superiority in numbers of soldiers. The pre-invasion bombing from April through July eliminated many of the Japanese troops.

Beginning July 17, three U.S. Navy Underwater Demolition Teams (UDT's) spent four nights clearing underwater obstacles from the reefs in front of assault beaches. Obstacles consisted of palm log cribs filled with coral and concrete and linked with wire cable. By midnight prior to W-Day, demolition teams had eliminated 640 obstacles off-shore of Asan Beach and 300 off-shore of Agat Beach (Lodge 1998:35).

U.S. Military map planning invasion strategies on Asan and Agat beaches (Rogers 1995:183).

American soldiers searching rice paddies and damaged coconut groves for enemy troops in Asan (U.S. Marine Corps 1944).

Asan Invasion Beach, with damaged rice paddies and coconut groves in the foreground and the U.S. War Ships in the background (U.S. Marine Corps 1944).