Despite suffering a resounding defeat at Midway in June 1942, the Japanese remained a fearsome adversary. Not only did they outnumbered US forces in every corner of the Pacific, efforts on the American home front to scale up for war were still in their infancy, and large volumes of new troops, ships, and planes had not yet arrived in the Pacific Theater.
The war would not wait, as an important discovery in the South Pacific prompted the first major US offensive. A reconnaissance flight had spotted the construction of a Japanese airfield on Guadalcanal, a sprawling island in the Solomon Islands, from where long-range bombers could disrupt shipping traffic between the United States and Australia, a key US ally. In August 1942, 11,000 men of the 1st Marine Division landed on Guadalcanal, seizing the lightly defended and unfinished airfield after a short march inland.
The Japanese had few forces on Guadalcanal but a substantial air base at Rabaul, just 550 miles away. They launched air strikes against the American support ships operating offshore, and though naval fighter planes warded off most of the attackers, the US aircraft carriers were forced to withdraw after heavy losses among their fighter groups. Hours later, Japanese ships sank four American and Australian cruisers in nighttime action, killing 1,200 Allied sailors. The remaining US ships fled for safer waters, leaving the Marines on Guadalcanal entirely isolated with no support and little food and ammunition.
As the Marines dug into their perimeter defenses—the reinforced Japanese were determined to re-take the position—naval construction troops, known as Seabees, hurried to finish construction of the airstrip so air support could arrive. The moment it was operational, Marine fighter planes and dive-bombers touched down, providing a substantial boost to the ground defenses. The pilots flew their battered planes from sunup to sundown, dueling daily with the Japanese in the skies above and pouncing on enemy barges and ships ferrying additional troops and supplies to the island.
For six months, the battle raged on the ground, at sea, and in the air. The Japanese troops on the island were unable to dislodge the Americans and as their own numbers and supplies dwindled, they resorted to desperate banzai charges. The frenzied, midnight raids, led by sword-waving officers, unnerved the Marines but they stood their ground each time, pouring machine-gun fire into the oncoming attackers. The number of Japanese dead rose rapidly, and by February 1943, Tokyo recognized the futility of further action and ordered all remaining troops evacuated from the island.
Both sides paid a steep price for that single airstrip, with the Japanese losing more than 24,000 men on the island. American ground casualties were far fewer, but each side lost thousands more in the ongoing sea and air battles. The battle ended decisively in favor of the United States, but the ferocity among the Japanese foreshadowed the grim work ahead in pushing the enemy back across the Pacific.