 Complete the following phrase:  During the campaign, most of the Japanese aircraft based in the South Pacific were redeployed to the defense of Guadalcanal. Many were lost in numerous engagements with the Allied air forces based at Henderson Field as well as carrier-based aircraft. Meanwhile, Japanese ground forces launched repeated attacks on heavily defended US positions around Henderson Field, in which the Japanese suffered appalling casualties. To sustain these offensives, resupply was carried out by Japanese convoys, termed the Tokyo Express by the Allies. The convoys often faced night battles with enemy naval forces in which they expended destroyers that the IJN could ill-afford to lose. Fleet battles involving heavier ships and even daytime carrier battles resulted in a stretch of water near Guadalcanal becoming known as Ironbottom Sound from the multitude of ships sunk on both sides. However, the Allies were much better able to replace these losses. Finally recognizing that the campaign to recapture Henderson Field and secure Guadalcanal had simply become too costly to continue, the Japanese 