The Prize: The Epic Quest for Oil, Money, and Power

by Daniel Yergin

The specific weakness was the vulnerability of Japanese shipping to submarines. Military planners had given surprisingly little thought to that risk. They underestimated both American submarines and the men who would sail on them. The Japanese thought Americans would be too soft and luxury-loving to stand up to the rigors of undersea living and warfare. In fact, America’s submarines were the best in the war; and once equipped with improved torpedoes, they were a deadly weapon that weakened and then ruptured the critical shipping links between the Southern Zone and the Home Islands. The long, drawn-out confrontation became known as the Battle of the Marus, after the term the Japanese used to describe all merchantmen. But only in late 1943 did the Japanese begin to give serious attention to the protection of shipping against submarines, including the establishment of convoys. Their efforts were inadequate and incomplete. “When we requested air cover,” one convoy commander said ruefully, “only American planes showed up.” The Japanese shipping losses continued to mount.5 Moreover, convoys created their own problems, which actually aided the Allies. Assembling and directing the movement of convoys required the generation of a network of radio signals that, among other things, announced exact “noon positions.” The interception of these messages by the Americans, who had cracked the Japanese codes, provided vitally useful information for the submariners. Overall, the consequences...