This operation was fought during the Pacific war on this group of islands situated in the central Solomons. US forces invaded them as part of an American offensive (CARTWHEEL) to isolate and neutralize Rabaul, the main Japanese base in their South-East Area.
On 20 June 1943 a Raider battalion (, 5(f)) landed at Segi Point on the main island, New Georgia, and during the next two weeks there were other landings by US Marines and 43rd US Division on Rendova and Vangunu islands, and on western New Georgia, to seize a Japanese airstrip at Munda point. Despite the US Navy's intervention, which resulted in the battles of Kula Gulf and Kolombangara, 4,000 reinforcements were successfully dispatched to the commander of the 10,500-strong Japanese garrison, Maj-General Sasaki Noboru. Most reinforced Munda, which became the focus of Japanese resistance, and their night infiltration tactics unnerved the inexperienced US troops. Non-battle casualties, caused by exhaustion and ‘war neuroses’, increased alarmingly, and when the commander of 14th Corps, Maj-General Oscar Griswold, arrived on 11 July he reported the division was ‘about to fold up’. The 37th US Division was brought in, Griswold replaced the worst affected units, and he then launched a corps attack on 25 July. Fierce fighting followed but by 1August the Japanese, outnumbered and outgunned, had withdrawn inland. This time US Navy destroyers prevented more reinforcements reaching them when, on the night of 6/7August, they sank three Japanese transports (battle of Vella Gulf).
Munda now became the base of Marine Corps squadrons which supported landings on Vella Lavella on 15 August. These bypassed and isolated Sasaki's garrison now gathering on Kolombangara after further US reinforcements, elements of 25th US Division, had failed to destroy them on New Georgia. On 15 September Sasaki was ordered to withdraw. In a brilliantly organized evacuation 9,400 men out of the 12,500 on Kolombangara were rescued by landing craft, and the following month those on Vella Lavella were also evacuated.
The campaign proved costly for the Americans who had 1,094 killed and 3,873 wounded with thousands more becoming non-battle casualties. Excluding the fighting on Vella Lavella, 2,483 Japanese bodies were counted. Planned as a one-division operation, the Japanese garrison's ‘skill, tenacity, and valor’—to quote the campaign's official US historian—eventually made it one where elements of four had to be used. ‘The obstinate General Sasaki,’ the same historian concludes, ‘deserved his country's gratitude for his gallant and able conduct.’