



Marshall Islands Campaign

Contributor: C. Peter Chen

ww2dbaseAbout 4,000 kilometers southwest of the Hawaii Islands, the Marshall Islands represented part of the perimeter of the Japanese Pacific empire. The former German colony was given to Japan after the closure of WW1, and had since been an important part of both offensive and defensive plans of the Japanese Navy. By the end of 1943, Admiral Mineichi Koga of the Japanese Combined Fleet knew the Americans were eyeing the islands, but he could not figure out where they would strike. His difficulties were further complicated by the lack of carrier aircraft, as they were taken away from him in an attempt to reinforce land-based squadrons. With his hands tied, all Koga could do was to send his submarines out as forward observers and order the regional commander in Truk Admiral Masashi Kobayashi to reinforce the island garrisons that were most exposed to American attacks. Kobayashi shifted men to the outer islands of Jaluit, Mili, Wotje, and Maloelap. In total, Kobayashi had 28,000 troops available to him in the Marshall Islands. For a garrison that size ground fortifications were sub-par, but that was rather by design at this stage of the war, for that Tokyo had since decided that the Marshall Islands were to serve only as a part of a delay action campaign. The new defensive perimeter was to be established much closer to the home islands.

ww2dbaseAmerican intelligence decoded Japanese messages and detected movements for the outer islands, and decided to change the invasion plans. Unbeknownst to the Japanese, the Americans were now bypassing the reinforced outer islands; they were now directly attacking Kwajalein and Eniwetok.

ww2dbasePrelude

Nov-Dec 1943

ww2dbaseRear Admiral J. H. Hoover's land-based B-24 Liberator bombers and other attack aircraft of the 7th Air Force from Ellice and Gilbert Islands attacked Mille and Maloelap as early as Nov 1943. ON 3 Dec, Rear Admiral Charles Pownall's Task Force 50 launched a carrier strike against Kwajalein with planes from four fleet carriers and two light carriers. The strike destroyed four transports and fifty Japanese aircraft, though the damage achieved little strategic importance. Upon recovery of the planes, Pownall cancelled a planned second strike against the Wotje Atoll in fear of a Japanese counterattack. The counterattack came in the form of night bombing attacks, which the Americans had no means of defense from the air since the American pilots had no night flight training. Lexington took a torpedo hit in one of the night strikes, but the entire task force would eventually return to Pearl Harbor.

ww2dbaseMajuro atoll was named to be a forward base in preparation of the invasion. Rear Admiral Harry Hill landed the Reconnaissance Company of the V Amphibious Corps of the United States Marine Corps and the 2nd Battalion of the 106th Infantry of the US Army's 7th Infantry Division, taking the lightly defended atoll on 31 Jan without any casualties.

ww2dbaseBattle of Kwajalein Atoll

29 Jan-3 Feb 1944

ww2dbaseLogistical problems caused the invasion plans against the Marshall Islands to become delayed for one month, but as soon as Chester Nimitz could gather all the troop transports he needed, he launched Operation Flintlock against the Kwajalein atoll in the south. Rear Admiral Richmond Turner commanded the forces against Kwajalein Island, with Major General Charles Corlett's 7th Infantry Division of the US Army on board. Rear Admiral Richard Connolly, with Major General Harry Schmidt's 4th Marine Division, sailed the Roi-Namur Islands in the north. Rear Admiral Harry Hill's task force was designated the reserve force ready to assist any of the two invasion forces after securing Majuro. The entire operation was covered in the sky by Vice Admiral Marc Mitscher's planes from six fleet carriers and six light carriers, which was escorted by eight battleships and a full compliment of cruisers and destroyers.

ww2dbaseOverall The Japanese garrison at the Kwajalein atoll consisted of 8,000 men, but only half of them were combat capable. The other half consisted of conscripts, laborers (many of whom were Koreans), and the Navy's aircraft support personnel. Rear Admiral Monzo Akiyama, located on Kwajalein Island, knew he lacked strong fortifications but his capability to coordinate a damaging aerial counterattack potentially could make up for his shortfalls.

ww2dbaseThe opening chapter of the invasion destroyed On 29 Jan 1944, American carrier aircraft attacked Roi-Namur, destroying 92 of the 110 Japanese aircraft that survived the pre-invasion strikes over the previous two months. Akiyama had just lost his ability to mount an effective aerial counterstrike.

ww2dbaseThe Roi-Namur invasion started smoothly on 31 Jan on five nearby small islands, but weather and inexperience in amphibious operations caused major confusion and delays during the actual landing on Roi-Namur on the next day. Nevertheless, luck stood with the Americans as Japanese resistance was much lighter than expected after the successful pre-invasion aerial and naval bombardment. The landers only faced a garrison of 300 Japanese. Roi-Namur was secured with only 51 Japanese survived out of the garrison of 3,000 men.

ww2dbaseAfter a similar first phase of capturing smaller outlying islands in the atoll on 31 Jan, the 1 Feb southern Kwajalein landings went much more smoothly. The 7th Infantry Division's men, vehicles, and equipment were unloaded with order and efficiency. Part of the reason was because most of the Japanese defenses were established on the ocean side of the island instead of the reef siding; when the defenses were constructed, the Americans had not yet achieved the ability to traverse over coral reefs. Another reason was an effective pre-landing bombardment. Commander Anthony Kimmins of the British Royal Navy observed the American landings at Kwajalein, and was amazed at the effectiveness of the pre-invasion bombardment. He said

"Nothing could have lived through that sea and air bombardment. [The bombardment] was the most damaging thing I have ever seen. [Ashore] I have never seen such a shambled in my life. As you got ashore the beach was a mass of highly colored fish that had been thrown up there by nearby explosions."

ww2dbaseHe commented that the bombardment was "the most brilliant success" he ever witnessed.

ww2dbaseAkiyama countered the Americans with a series of fierce infantry charges backed by strong bunkers and pillboxes when the Americans advanced. By the start of 2 Feb, only 1,500 out of the original 5,000 garrison were still alive. Much like Roi-Namur, by the time the island was secured, only 265 men survived as captured prisoners; all the rest perished. The Americans lost one for every 100 killed.

ww2dbaseBattle of Eniwetok Atoll

17-21 Feb 1944

ww2dbaseEniwetok was an atoll with a series of small islands and islets offering little more than two square miles of land, but the location was strategic, for that they could provide airfields for the subsequent invasion of the Marianas. Major General Yoshimi Nishida bolstered the defenses of the main island some time before Jan 1944, but the small size of the island meant that defense in depth was nearly impossible. Any American attempt to invade the island must be stopped at the beaches, otherwise the main island of Eniwetok would be lost. The main island was guarded by 4,000 men, of which about half were of the Japanese Army and the other half various naval personnel.

ww2dbaseThe invasion, Operation Catchpole, began with a naval bombardment on 17 Feb, while 8,000 Marines and 2,000 Army infantry waited aboard transports. On the same day, the 22nd Marine Regiment commanded by Colonel John Walker on Engebi Island in the northern side of the atoll. The Engebi landing was a logistical nightmare that embarrassed Marine Corps Brigadier General Watson who oversaw the operation, though he made up his initial mistakes by securing the island at a casualty count of only 85. On 19 Feb, the 106th Infantry Regiment landed on the main island of Eniwetok after only a brief bombardment. The brief bombardment proved to be ineffective. With automatic fire cris-crossing the landing beaches, American men and equipment soon formed a congested mess, repeating the same logistical nightmare that haunted the invaders. Nevertheless, the island was secured by 21 Feb at the loss of 37 Americans; similarly, nearly the entire 800-strong Japanese garrison died. Next, Watson led his Marines (leaving the Army to occupy Eniwetok Island) to Parry Island. The landers faced similar defenses on Parry, but the logistical problems were averted by a thorough naval bombardment led by battleships Tennessee and Pennsylvania, delivering over 900 tons of explosives on the Japanese defenses before the 22nd Marine Regiment made their landing. Parry Island was secured the next day.

ww2dbaseWith the Marshall Islands under American control ten weeks ahead of schedule, Allied engineers started to construct the islands as forward bases for the next phase of the island hopping campaign toward the Japanese home islands.

ww2dbaseSources: The Pacific Campaign, Wikipedia

Last Major Update: Sep 2006

Marshall Islands Campaign Interactive Map

Marshall Islands Campaign Timeline

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