The Philippines lay roughly 1,700 nautical miles from Japan. B-17G and B-25H figures show how even long-range bombers could reach only a limited part of the home islands from those bases. Every bomb used offensively also reduced the stock available to defend the Philippines against a later Japanese attack. Sustained operations would therefore require ammunition, fuel, replacement aircraft, and other supplies to cross the Pacific in escorted convoys. Routes through the South Seas Mandate risked interception by Japanese carriers and Kongō-class capital ships, while routes through British and Dominion islands could compromise their neutrality. Japan could use those reinforcement movements as repeated attrition opportunities without first assaulting the Philippine bases.
Notable Point · 1:07:14-1:11:38
Philippine bomber range and the convoy attrition trap
Bombers in the Philippines could reach only part of Japan and would turn every sustained offensive into an exposed trans-Pacific supply problem.