A small naval base had been established on Chichijima in 1914. The island was the primary site of long range Japanese radio stations during World War II, as well as being the central base of supply and communication between Japan and the Ogasawara Islands. As behooved this status it had the heaviest garrison in the Nanpō Shotō. According to one source: "At the time of the Japanese attack on Pearl Harbor an Army force of about 3,700-3,800 men garrisoned Chichi Jima. In addition, about 1,200 naval personnel manned the Chichi Jima Naval Base, a small seaplane base, the radio and weather station, and various gunboat, subchaser, and minesweeping units." The garrison also included a heavy artillery fortress regiment, it was a frequent target of US attacks. A young George H. W. Bush was shot down while on one of these raids. In 1944, all of the 6,886 civilian inhabitants were ordered to evacuate from the Ogasawara islands. Japanese troops and resources from Chichijima were used in reinforcing the strategic point of Iwo Jima before the historic battle that took place there from February 19 to March 24, 1945. The island also served as a major point for Japanese radio relay communication and surveillance operations in the Pacific, with two radio stations atop its two mountains being the primary goal of multiple bombing attempts by the US Navy.