another Japanese attempt to reinforce the island. The evacuation was carefully planned to take place in three destroyer lifts and would begin in late January 1943. The first operation was conducted with 20 destroyers on February 1, another with 20 destroyers was conducted on February 4. A third and final operation was conducted with 18 destroyers on February 7. Operation Ke was successful and 10,652 men, were evacuated from Guadalcanal, with Japanese losses only being a single destroyer. Central Solomons and New Guinea With Guadalcanal lost, the Japanese focus shifted to the Central Solomons and New Guinea. However, during the Battle of the Bismarck Sea on March 2–4, an Allied air attack destroyed a convoy attempting to move troops from Rabaul to Lae on New Guinea. To rectify Japan's declining position, Yamamoto devised a major air offensive to counter the growing Allied strength in the Solomons. He moved the air groups of the Combined Fleet's four carriers of about 160 aircraft, to Rabaul to join the 190 aircraft of the Eleventh Air Fleet. This brought the Japanese air strength there to some 350 aircraft. The air offensive was codenamed Operation I-Go consisting of four major attacks conducted on Allied positions on Guadalcanal, Buna, Port Moresby and Milne Bay on April 7, 11, 12 and 14, respectively. In mid-April, the Japanese concluded the operation claiming success against Allied shipping and defending fighters. In fact, little had been achieved and Japanese losses were heavier than those suffered by the Allies, resulting in further attrition to the vital Japanese carrier aircrews. During 1943, the IJN attempted to preserve its strength in the face of two attack routes by the Americans. In the Solomons, the action turned to the Central and Northern Solomons between March and November. During this period, the Japanese and Americans fought seven surface engagements, all of these actions were fought at night during which the Japanese still enjoyed an advantage. Twice, Japanese destroyers defeated an Allied force composed of cruisers and destroyer, demonstrating to the Americans, Japanese prowess at night fighting. In early August, at Vella Gulf, three out of four Japanese destroyers were sunk by American destroyers using radar with a new doctrine which emphasized torpedo attacks. It was the first time in the war that the Japanese destroyers had been beaten during a night battle. The next action, fought on August 18, was indecisive. On October 6, the