Operation Creosote

'Creosote' was the US geographical rather than operational codename for Wotje atoll in the central portion of the eastern Radak group of the Marshall islands group in the central Pacific (1941/45).

Wotje is 164 miles (264 km) to the east of Kwajalein, and is considered part of the Romanzow group together with the small Erikub atoll to the south and a few scattered islands between the two atolls. Wotje has 75 islands and islets with a total land area of 3.16 sq miles (8.18 km˛), and in overall size is 30 miles (48 km) long on its east/west axis and between 6 and 12 miles (12.9 and 19.25 km) wide. Most of the atoll’s islands and islets are located along its eastern rim, where the largest islands are located, the central southern side, and a few scattered along the west northern side. The largest island is Wotje on the extreme east central end.

Wotje’s large lagoon had the area for 2,000 ships to anchor, and could be accessed via four passes. The island was also large enough for the construction of an airfield, making it an excellent candidate for development as a naval base. The Japanese had constructed perhaps their strongest base in the Marshall islands group on Wotje by 1941, with 3,450- and 4,920-ft (1050- and 1500-m) runways at Otdia air base, but no aircraft had been deployed to this base by the time of the Pacific War’s start. There was also a seaplane base, numerous anti-aircraft and coast-defence artillery batteries, and a system of roads and trenches. The atoll was garrisoned by the 53rd Guard Force, which arrived just before war broke out.

Like Jaluit, Maloelap and Mille, Jaluit was subordinate to the 6th Base Force, headquartered on Kwajalein and formed in De­cember 1941, itself under the command of the 4th Fleet headquartered on Truk atoll in the Caroline islands group. During October and November 1941 the 51st, 52nd and 53d Guard Forces were sent to defend Jaluit, Maloelap and Wotje respectively. In the summer of 1943 these guard forces were redesignated as the 62nd, 63rd and 64th Guard Forces respectively. The new 66th Guard Force was assigned in June to Mille. which was intended for use as an aircraft staging base for offensive operations into the Ellice, Fiji and Samoa island groups.

Imperial Japanese army units began to arrive in the Marshall islands group late on 1943 as the new National Defence Zone was established. Among these units was the 3/107th Regiment of the 52nd Division, which was assigned to Mille.

The senior Japanese naval commander in the bypassed atolls of the Marshall islands group was Rear Admiral Nisuke Masuda, who had his headquarters on Jaluit.

In the period paving the way to 'Flintlock' at the end of January 1944, the Americans knew that it was essential for the airfields on these atolls be neutralised and thereby ensure the security of the invasion fleet. The bases had been attacked from the air during the 'Galvanic' campaign to tale key part of the Gilbert islands group, but from November 1943 they were attacked repeatedly by powerful carrier-based air formations as well as land-based bombers, the latter launched from the bases in the Ellice islands group and on Canton island. The first attacks after the end of 'Galvanic' struck Mille, Jaluit and Maloelap on 18, 23 and 26 November respectively. Jaluit, from which the Japanese had withdrawn most of their aircraft, was effectively neutralised on the same day as the first attack, but the raids were nonetheless maintained. Mille had been neutralised by 2 December, but Maloelap did not succumb until 2 January 1944. Attacks on Wotje were not started until 13 December, and by 26 December Wotje had been rendered impotent. Raids continued on all these atolls through the 'Catchpole' campaign in the Marshall islands group with the object of further degrading the Japanese defensive capability.

There were 13,700 Japanese navy and army personnel, as well as numbers of civilians on the four atolls: 2,200 on Jaluit, 3,100 on Maloelap, 3,300 on Wotje and 5,100 on Mille.

After the capture of the key elements of the Marshall islands group, these four islands were bypassed by the US forces and effectively taken under siege by the 4th Marine Base Defense Air Wing on Kwajalein, with its aircraft groups operating from Engebi in Eniwetok atoll, Roi in Kwajalein atoll, and Majuro atoll. Navy and army warplanes also participated in the reduction of the bypassed island bases of the Marshalls group.

The campaign after that in the Marshall islands group started in March 1944 and lasted until the war’s end. Including those of the effort before the Marshall islands group campaign and the attacks during the campaign, the US air forces dropped almost 13,000 tons of bombs on Japanese installations on these four atolls. While the Japanese arguably became some of the most practised anti-aircraft gunners in the Pacific War, for the US airmen it was a monotonous campaign of daily 'milk runs' in a seemingly endless effort to destroy the garrisons. The attempts of the isolated Japanese garrison forces to grow crops were countered by fire bombings and aerial spraying with Diesel fuel.

Of the 13,700 Japanese on the four atolls, by the time World War II ended on 15 August 1945, 2,564 had been killed and 4,876 had died of disease and starvation. On all of the islands except Jaluit, where Masuda managed to maintain morale and pre­vent starvation, the defenders of the other islands were wholly demoralised by the war’s end. On 2 September 1945, on Truk, Vice Admiral Chuichi Hara, commander of the 4th Fleet, and Lieutenant General Shunsaburo Mugikura, commander of the 31st Army, signed a surrender which also applied to the isolated garrison forces in the Marshall islands group. Masuda committed suicide rather than answer questions regarding the fate of missing airmen who had been shot down over the islands.