Java Sea, a part of the Pacific Ocean. To the north is Borneo; to the east, Celebes; to the south, Java; and to the west, Sumatra. The Java Sea is about 950 miles (1,500 km) long (east-west) and up to 300 miles (480 km) wide. Much of the sea is quite shallow—less than 200 feet (60 m) deep. Karimata Strait leads northwestward to the South China Sea, Makassar Strait northeastward to the Celebes Sea, and Sunda Strait southwestward to the Indian Ocean. In a battle fought here February 27–28, 1942, during World War II, the Japanese defeated combined British, Dutch, American, and Australian naval forces.