Battle of Cape Esperance: One Misread Roger and a Night of Chaos

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By October 1942 the fight for Guadalcanal turned on Henderson Field. Planes of the Cactus Air Force ruled the waters by day, while Japanese destroyers of the Tokyo Express, which Japan called rat transportation, ran supplies down the Slot by night. Rear Admiral Norman Scott led Task Force 64 to break that pattern on the night of October 11. Japan sent a supply convoy under Rear Admiral Takatsugu Jojima and a separate bombardment force of three heavy cruisers and two destroyers under Rear Admiral Aritomo Goto, who expected no American ships at night. Two American cruisers, Helena and Boise, carried the new SG microwave radar with a map-like screen, yet Scott chose the San Francisco, with older radar, as his flagship.

A botched column turn at 2333 scattered Scott's three lead destroyers just as Helena's radar found Goto's ships about 27,000 yards out. Scott assumed the contacts were his own lost destroyers. At 5,000 yards Helena asked for permission to fire with interrogatory Roger, and Scott's reply of Roger, which meant only that he had received the message, was taken as a green light. Goto, convinced the ships were friendly, flashed recognition lights as up to 40 shells struck his flagship Aoba and mortally wounded him. Scott, believing he was shooting his own men, ordered a ceasefire that some ships ignored. The Americans claimed a tactical win, but Jojima's convoy landed its troops, and the Navy drew the wrong lesson about Japanese torpedoes.

• Japanese lookouts relied on large-aperture binoculars and were trained to look slightly off center to catch faint silhouettes.
• The destroyer Duncan made a solo torpedo run, was hit by both sides, and was lost.
• Two shells from the Kinugasa penetrated Boise's magazine, and inrushing seawater quenched the fire seconds before the powder blew.
• Two days later, two Japanese battleships fired more than 900 fourteen-inch shells into Henderson Field.
• The overlooked Type 93 Long Lance torpedo, oxygen fueled and nearly wakeless, punished the U.S. Navy at Tassafaronga two months later.