The territory under Japanese mandate comprises the former German colonial possessions in the Pacific Ocean lying north of the equator. This region is made up of three main groups of islands, the Marshall, the Mariana, and the Caroline, having a total estimated land area of approximately 800 square miles. Included in these groups are more than 1,400 islets, reefs, and atolls stretching across the Pacific from 130 longitude east to 175 longitude east, and from the equator to 22 latitude north. Lying west of Hawaii, east of the Philippines, and south of Japan, many of these islands are near the steamship lanes running from the Hawaiian Islands to Guam and to the Philippines.

A recent census shows that there are more than 60,000 inhabitants in the territory under Japanese mandate, about four-fifths being natives. More than 12,000 Japanese have gone to the islands, as well as a few Europeans and Americans. The Japanese, for the most part, are engaged in agricultural or commercial pursuits or are government officials, while the Occidental population is made up mostly of missionaries. Racially, it is believed that the natives come within the Micronesian or Polynesian classification, although in many instances the racial strain is not pure.

Prior to 1914, the Japanese had few interests of importance in these islands. Occasional tramp steamers, trading vessels, or fishing boats from. Japan sometimes visited them, but no regular trade relations existed. When, however, the World War broke out, Japan lost no time in sending a naval squadron to the islands, and, with comparative ease, she obtained control of them in October, 1914. At the time, the Tokio government explained that the seizure of the islands was only temporary, for military purposes, and that Japan had no desire to keep them. Later events indicate, however, that these mere dots in the Pacific took on an increased value in Japanese eyes; certainly, once having secured control of them, the conqueror was loath to give them up.