Operation Starvation was a US Army Air Forces aerial mining campaign launched on March 27, 1945, when 102 Boeing B-29 Superfortresses lifted off from Tinian to sow thousands of mines in Japanese harbors and sea lanes. The five-month campaign effectively strangled Japan’s maritime supply lines before hostilities ended.
For months, the XXI Bomber Command focused its heavy bombers on incendiary raids against urban centers. But behind closed doors, a quieter, deadlier strategy was taking shape. Lieutenant Commander Ellis Johnson, a magnetism specialist and Naval Ordnance Laboratory consultant working for Admiral Chester Nimitz, had engineered a plan to deploy sea mines from the air.
Most Army Air Forces leaders initially dismissed the proposal as a distraction from strategic bombing. Unfazed, Nimitz took the issue directly to General Henry “Hap” Arnold, who reluctantly agreed to a delayed and reduced schedule. Arnold handed execution over to General Curtis LeMay in January 1945. LeMay quickly backed the plan and ordered a full wing strength deployment against the Shimonoseki Strait.
The First Night Over the Shimonoseki Strait
Late on the afternoon of March 27, 1945, the 313th Bombardment Wing initiated the campaign. Brigadier General John H. Davies piloted the lead aircraft as 102 bombers took off from Tinian carrying roughly a dozen sea mines each. Ninety-two of those B-29s successfully mined the narrow shipping channel separating Honshu and Kyushu.
Japanese anti-aircraft batteries and searchlights met the incoming fleet, costing the wing three B-29s over the strait alongside eight damaged aircraft, according to historian Richard P. Hallion. The weapons themselves relied on sophisticated magnetic and acoustic firing mechanisms, which were later augmented by pressure triggers designed to detonate as a ship’s hull altered local water pressure. A typical combat load consisted of twelve 1,000-pound mines or seven 2,000-pound variants.
Five Phases of Economic Strangulation
Hallion divides Operation Starvation into five distinct phases running from March 27 to August 15, 1945. The initial push supported the invasion of Okinawa by sealing off the Shimonoseki Strait. Subsequent phases targeted the Inland Sea, Kobe, Osaka, Tokyo, the ports of northwest Honshu and Kyushu, and eventually Korean ports.
The operational toll on Japanese logistics proved catastrophic. Tonnage moving through the Shimonoseki Strait plummeted from roughly 70,000 tons per day in March to 7,500 tons in May, sinking to 1,750 tons by June. Shipping through Kobe dropped by 85 percent between March and July, forcing the abandonment of 35 out of 47 essential convoy routes.
| Metric | US Strategic Bombing Survey | Richard P. Hallion | Wikipedia / USNI Proceedings |
|---|---|---|---|
| Total Mines Sown | 12,034 | ~12,000 | 12,135 |
| Sorties Flown | – | – | 1,533 |
| Ships Sunk or Damaged | – | 961 | 670 |
| Tonnage Affected | – | ~2,000,000 tons | >1,250,000 tons |
| Aircraft Lost | – | 15 | 16 |
Japanese countermeasures, including minesweepers and specialized suicide boats designed to trigger the ordinance prematurely, failed to secure the sea lanes. Following the war, Imperial Japanese Navy minesweeping expert Captain Kyuzo Tamura remarked that the bombing campaign effectively starved the nation.
B-29 Mines Sank Half of Japanese Ships
The US Strategic Bombing Survey published in July 1946 concluded that mines dropped by B-29s accounted for 50 percent of all Japanese ships sunk or damaged after April 1945. The report noted that an earlier start to the campaign could have achieved economic strangulation with significantly less duplicated effort.
The operation cost the XXI Bomber Command 15 to 16 aircraft and approximately 103 airmen killed. Accounting for just 5.9 percent of the command’s successful sorties, the mining effort yielded a devastating return on investment compared to traditional submarine warfare. While firebombing campaigns dominated public awareness, Operation Starvation quietly closed the waters that sustained the Japanese empire.
