The Battle off Samar was the centermost action of the Battle of Leyte Gulf, one of the largest naval battles in history, which took place in the Philippine Sea off Samar Island, in the Philippines on October 25, 1944. It was the only major action in the larger battle in which the Americans were largely unprepared. After the previous day's fighting, the Imperial Japanese Navy's First Mobile Striking Force, under the command of Takeo Kurita, had suffered significant damage and appeared to be retreating westward. However, by the next morning, the Japanese force had turned around and resumed its advance toward Leyte Gulf. With Admiral William Halsey Jr. lured into taking his powerful Third Fleet north after a decoy fleet and the Seventh Fleet engaged to the south, the recently landed 130,000 men of the Sixth Army were left vulnerable to Japanese attack on Leyte.
Kurita, aboard the Japanese battleship Yamato, took his large force of battleships, cruisers and destroyers from the San Bernardino Strait and headed south toward Leyte, where they encountered Task Unit 77.4.3 ("Taffy 3"), the northernmost of the three escort carrier groups under Rear Admiral Clifton Sprague that comprised the only American forces remaining in the area. Composed of only six small escort carriers, three destroyers, and four destroyer escorts, Taffy 3 was intended to provide shore support and anti-submarine patrols, and did not have guns capable of penetrating the Japanese armor. The Japanese opened fire shortly after dawn, targeting Taffy 3's escort carriers, which Kurita mistook for the main carriers of the Third Fleet. The escort carriers fled for the cover of rain squalls and launched their aircraft in defense, while the three destroyers and destroyer escort USS Samuel B. Roberts, led by USS Johnston, launched a torpedo attack that sank one ship and sent the Japanese strike force into disarray.