Halsey's forces spent the rest of the year battling up the Solomon Islands chain to Bougainville. At Bougainville the Japanese had two airfields in the southern tip of the island, and another at the northernmost peninsula, with a fourth on Buki just across the northern passage. Here, instead of landing near the Japanese airfields and taking them away against the bulk of the Japanese defenders, Halsey landed his invasion force of 14,000 Marines in Empress Augusta Bay, about halfway up the west coast of Bougainville. There he had the Seabees clear and build their own airfield. Two days after the landing, a large cruiser force was sent down from Japan to Rabaul in preparation for a night engagement against Halsey's screening force and supply ships in Empress Augusta Bay. The Japanese had been conserving their naval forces over the past year, but now committed a force of seven heavy cruisers, along with one light cruiser and four destroyers. At Rabaul the force refueled in preparation for the coming night battle. Halsey had no surface forces anywhere near equivalent strength to oppose them. Battleships , , and assorted cruisers had been transferred to the Central Pacific to support the upcoming invasion of Tarawa. Other than the destroyer screen, the only force Halsey had available were the carrier air groups on and .