Operation Watchtower was the first major offensive by Allied forces against Japan. Between August 1942 and February 1943, the Allies battled their way through the Guadalcanal starting in the Solomon Islands. Victory would secure Allied supply and communication routes between the US, Australia, and New Zealand, as well as secure an airfield (Henderson Field) that was under construction on Guadalcanal. Despite large counterattacks for the field by the Imperial Army, including the massive naval Battle of Guadalcanal, the Allies were able to hold the territory and the Japanese were forced to give up the fight.