In the late 19th century, the Japanese military began making maps of neighboring countries, Gaihozu. Beginning with Taiwan (1895), Japan's imperial territories eventually included Sakhalin, Korea, the Kwantung Leased Territory in China's current-day Liaodong Province, Manchuria, and the South Pacific Islands, along with countries occupied during World War II. For planning successful battles in foreign lands and to effectively govern colonized area, it became essential for Japan to create such maps as Gaihozu (外邦図).
At first, the Japanese military copied maps obtained from those countries or from the West. But army officers soon began sending teams to survey first the coastlines and then inland areas of China and Korea. These maps were either surveyed and drawn by Japanese surveying squads or reproduced from topographic maps drawn by the land surveys of other countries by an order of Land Survey Department of the General Staff Office, the former Japanese Army.
The area covered by the Gaihozu extends as far north as Alaska and Siberia, as far west as India and even Madagascar, and as far south as Australia. No one knows how many maps were made, mostly because the military kept its mapping program secret and ordered the maps destroyed as they became the target of confiscation by the occupation forces at the end of World War II.
Those captured Gaihozu were first sent to Washington D.C. and studied by the U.S. Map Service (AMS). Surplus map copies were eventually transferred to the Library of Congress, and finally distributed to universities all over the United States.
 Ryuta Itagaki, Satoshi Mizutani, and Hideaki Tobe, “Japanese Empire,” in The Ashgate Research Companion to Modern Imperial Histories, ed. Philippa Levine and John Marriott (Farnham, Surrey: Taylor & Francis, 2012), 251. ProQuest Ebook Central.
 Azusa Tanaka and Shigeru Kobayashi, "Gaihozu, Maps of the Areas Outside the Japanese Territory Prepared by the Former Japanese Army, in the Libraries in the United States: Discovery and Processing." (Manuscript submitted for publication, 2018), 1.