Kenneth E. Hunter, The war against Japan: Pictorial record (1952)
“ In the early fighting against the Japanese, the tropical battlegrounds of the South and Southwest Pacific imposed severe difficulties on the U.S. forces. Operations were hampered by a jungle-wise enemy whose tactics and weapons were well adapted to the terrain. In October 1942 U.S. commanders were directed to begin a program of training which would include specialized training in close-in fighting, judo, firing from trees and other elevated positions, map reading, and use of the compass for movement through dense undergrowth. ”
