The large, mountainous, and over populated Japanese Home Islands relied upon an inter-island convoy system for a functioning economy, and most importantly, food distribution. As early as the capture of the Mariana Islands in the summer of 1944, Admiral Nimitz floated an idea to disrupt this system by mining the choke points, but was unable to execute it. His carrier based planes had too short a range and the carriers would be subject to land based air and Kamikaze attack. Also, his submarines could not operate effectively in the narrow confines of the Japanese Home Islands. He turned to General Hap Arnold and the XX Air Force in an unheard of request for inter-service cooperation. He wanted the B-29s of Curtis LeMay’s XXI Bomber Command to slow down their wildly successful firebombing campaign against Japan’s wooden cities, and fill their bombers with sea mines. He wanted to drop them on inter-island convoy choke points identified by naval intelligence. It took until January 1945 to get the permission.
The US Army Air Force’s leadership in the Pentagon went into near apoplexy at this grievous breach of their domain. They were busy looking to the future and preparing the US Army Air Corps to become an independent branch of the United States Armed Forces. They finally had the numbers of bombers (This time for sho!) to put Italian airpower theorist Giulio Douhet’s theories into practice. And this close to the end of the war they didn’t want to be seen as subservient to any other branch. That they were during the invasion of France and the Battle of the Bulge was already being erased from institutional memory. The future was a post war US Air Force dominated by a Strategic Bomber Command, and nothing was going to get in the way, including ending the war faster.
However, they didn’t take into account LeMay’s determination to bring the war to Japan worse than they brought it to Pearl Harbor. Like the little girl shrugging her shoulders meme, LeMay saw no reason why he could not both firebomb Japan’s cities and choke them out of the war simultaneously. Although his men were about to get busy burning Japan’s cities to the ground, he also saw the value in starving them to death. Even before Washington and Arnold gave their approval, LeMay directed his planners to make it happen.
On 27 March 1945, B-29s dropped the first of more than 12,000 sea mines into the many straits and narrows of the Japanese Home Islands, in the aptly named Operation Starvation. Nimitz’ intelligence planners had correctly identified the Achilles Heel of Japan’s economy, and it ground to a halt. In the last four months of the war, mines shut down 37 of the 45 critical convoy lanes the Japanese relied upon for a functioning modern economy. Operation Starvation is credited with sinking a staggering 680 ships for the loss of only 15 B-29 bombers. It was more ship tonnage, 1.2 million, than all other Allied methods combined in the time period. Operation Starvation would have assuredly starved Japan out of the war by 1946.