as strong as they had been at the beginning of the war. Until May and June 1942, air losses had been limited and aircraft production had kept pace with losses. From the beginning of war through the end of June, Japanese naval aircraft losses totaled 1,641. Almost half of the losses occurred during the months when the battles of Coral Sea and Midway took place, with the large majority in June, including many at Midway. Over the same period Japanese aircraft deliveries numbered 1,620. Additionally what was not of a major concern was pilots, as aircrew casualties at Midway were not so severe and the large majority of aircrew of the Kido Butai returned despite the sinking of their ships. These were bolstered by 2,000 newly trained pilots in 1942. Guadalcanal and the Solomons (1942-43) On August 7, 1942, U.S. Marines landed on the islands of Guadalcanal and Tulagi in the Solomons, putting the Japanese on the strategic defensive for the first time in the war. Vice Admiral Gunichi Mikawa, commander of the newly formed Eighth Fleet at Rabaul, reacted swiftly. Gathering five heavy cruisers, two light cruisers, and a destroyer, he sailed south and attacked the Allied naval force off the coast on the night of August 8–9. Mikawa's quick response resulted in the Battle of Savo Island, in which four Allied heavy cruisers were sunk with no Japanese ships lost. This was the worst defeat ever suffered by the U.S. Navy while at sea, only mitigated by the failure of the Japanese to attack the vulnerable American transports. Aside from Mikawa's initial reaction, the Japanese were slow to respond, seeing the American landings as a reconnaissance-in-force, but by mid-August they had assembled four battleships, five carriers, 16 cruisers, and 30 destroyers to dislodge the Americans. On August 24–25, the IJN launched an operation intended to send a small transport convoy to the island and also to destroy any American naval vessels in the area. The ensuing Battle of the Eastern Solomons was the third carrier battle of the war. The IJN achieved neither of their goals, with the convoy diverted to the Shortland Islands and the American navy still present. Japanese losses were heavy with 75 carrier aircraft, a light carrier, a transport, and a destroyer lost. Although the American carrier Enterprise was damaged, she managed to elude Japanese attempts to sink her. With the Americans' Henderson Field