No Pacific War campaign was so expensive—and important—as this brutal fight for Guadalcanal. For six months, this tiny island was the battleground of unrelenting warfare, where dominance of the seas that surrounded it, of the air space above it, and of the balance of power in the Pacific was contested to the death.
Guadalcanal waters wore the dark nickname Iron Bottom Sound, a deadly swallowing of over a hundred ships and thousands of planes, their wreckage silently rotting on the ocean floor as a hellish testament to the ferocity of the battle. The strategic value of the island became apparent: it was roughly 1,000 kilometers northeast of Australia, protecting a critical sea route between the United States, Australia, and New Zealand.
Japanese forces were pushing forward and building an airbase that would dominate this lifeline corridor by mid-1942. Whoever held the airbase would be holding the supply lines and putting Japan on the defensive for the Allies. American Marines launched a bold attack on Guadalcanal and the close neighbor Tulagi in August 1942, catching the Japanese off guard and securing the half-finished airbase, which was subsequently renamed Henderson Field. Holding it was one thing.
The Imperial Japanese Navy, masters of night combat with their deadly Type 93 “Long Lance” torpedoes, attacked quietly. In the Battle of Savo Island, they had sunk four Allied cruisers within half an hour, brutally surprising the U.S. Navy.
That initial disillusionment made the Americans prudent in adversity. Radar, new and untested technology foisted upon naval combat, was soon after applied to fleet operations, giving American warships the ability to locate enemy warships hours prior to them being within eyesight. That advantage was valuable in October, during the Battle of Cape Esperance, when radar-directed fire caught Japanese ships staging a night attack off guard, placing the Allies in charge of their section of the receding edge.
It was November that saw some of the fiercest combat of the campaign: the First and Second Naval Battles of Guadalcanal. They were nighttime battles, and gargantuan, hand-to-hand street battles with bursts of gunfire that light up warships at close quarters. The Americans destroyed ships and two admirals in the first battle, but Henderson Field fell into Allied hands intact.
The following evening, the radar-directed USS Washington battleship poured a Wall of fire into the Japanese battleship Kirishima, which sank. Such was the effect of the new age of radar war on the oceans. A small Japanese destroyer squadron had returned the favor later, at Tassafaronga, replying with killing precision and torpedoing USS Northampton cruiser, sinking it and putting a few holes in others.
Alone, though victorious, the Guadalcanal Japanese command became desperate. Its troops were isolated, hungry, dispersed, and demoralized by constant Allied bombardments. Its reserves were depleted, disease broke out, and morale was shattered.
By February 1943, the Japanese had pulled back, and Guadalcanal was the Allies’ first true strategic victory of the war in the Pacific. It cost them tens of thousands killed, over 20,000 of them lost at sea in naval combat alone, Iron Bottom Sound becoming a great underwater graveyard littered with wrecks from both sides.
Years later, remotely operated submersibles and divers ventured into such warfields under the sea and surveyed the wrecks like Japan’s destroyer Teruzuki and USS New Orleans. Such expeditions not only render the scale of the war real but also keep alive the memories of the soldiers.
Those warships are no longer hollow specters; they’re memorials to settle, to courage, to sacrifice beyond recall. Out at sea off Guadalcanal, sea and naval Marines and sailors learned some tough lessons about radar, night warfare, and the coordination of aerial and naval power. The campaign did not merely chart the trajectory of Pacific War history—it revolutionized naval warfare in its very essence and continues to shape military doctrine today.