South Pacific Mandates (Japan), c. 1930.
“The islands of all sizes that constitute Japan Proper stretch like a bow. The silvery planes flying between Japan and the Palau (Pelew) Islands via Saipan suggest so many arrows shot from a bow … At a time like the present when a trans-Pacific air route is pregnant with political and economical significance, it is most important for Japan to develop her South Sea airline.
“… If the Pacific were to be divided into two spheres of influence between Japan and America, Jaluit would certainly constitute the eastern gateway to the East Asian sphere.
“In April, 1939, the four-engined Kawanishi Big Flying-Boat with accommodations for 17 passengers shuttled 2,500 miles between Yokohama and Palau over the ‘Black Current’ … The distance between Japan Proper and its ‘life-line’ in the South Seas is now covered in two days, planes plying twice a month.
“Intercourse between islands under Japanese mandate had hitherto been very inconvenient. The establishment of an air route in this part of the world marked an epoch in the history of intercourse between islands, as well as between Japan Proper and the islands.
– “Japan’s Air Route Over the Black Current”, by Takeo Ohkuo, The Far Eastern Review, July 1941