Notes on June 1945 War Planning: Kyushu Invasion and Stimson-Truman Discussions

Stimson on bombing strategy

• Source: Stimson diary, 6 June 1945, remarks to President Truman on the conduct of the war against Japan.
• Stimson’s point: trying to hold the Air Force down to precision bombing, but because the Japanese scattered their manufacture, it was difficult to prevent area bombing.
• Stimson’s two major concerns:
  • (1) He did not want the United States’ reputation to outdo Hitler in atrocities.
  • (2) He feared that before we could get the new weapon (the atomic bomb) ready, Japan could be so thoroughly bombed out that the new weapon would lack a fair background to demonstrate its strength.
• Truman’s reaction: he laughed and said he understood.

Truman’s 18 June 1945 meeting: review of invasion planning

• Truman met with advisers to review the planned invasion of Japan.
• Key planning note: a date around 1 November was considered, with attention to weather and minimizing Japanese time for defense preparations.
• Weather and timing:
  • If we delay much after the beginning of November, the weather in the following months could delay the invasion of Japan, and hence the end of the war, by as much as $6\ ext{months}$.
• Strategic objective: lodgement in Kyushu is essential to tighten the blockade and bombardment, and to force capitulation via invasion of the Tokyo Plain.
• Propositions on Japanese capitulation:
  • If the Japanese capitulate short of complete military defeat, it will likely occur when faced with (1) destruction already wrought by air bombardment and sea blockade, (2) a landing on Japan demonstrating resolve, and perhaps (3) the entry or threat of entry of Russia into the war.
• Administrative note: the material suggests a potential role for Russian entry as a lever toward capitulation.
• Target-date rationale (General Marshall’s note):
  • Target date of $1\ November\ 1945$ was selected because:
  • a. If we press preparations we can be ready.
  • b. Our air action will have smashed practically every industrial target worth hitting in Japan, as well as destroyed huge areas in the Jap cities.
  • c. The Japanese Navy, if any still exists, will be completely powerless.
  • d. Our rear action and air power will have cut the Jap reinforcement capability from the mainland to negligible proportions.
• Casualty context: the first 30 days in Kyushu should not exceed the price paid for Luzon (the Philippines, where $31{,}000$ Americans were killed, wounded, or missing).
• Ethical/practical note: there is a grim fact that there is not an easy, bloodless path to victory in war.
• Russian participation: there is an important point about Russian participation—the impact of Russian entry on an already hopeless Japanese position may be decisive, potentially levering capitulation at that time or shortly thereafter.
• Source cue: reprinted, with permission.

Kyushu invasion plan: stated goals and military rationale

• The plan enshrined in the discussion posits Kyushu as the target for the invasion to achieve strategic objectives:
  • General Marshall noted that Kyushu was the only viable course to pursue.
  • He argued that air power alone was not sufficient to compel Japan to quit the war; just as air power alone could not force Germany out of the war.
  • For Japan, the opponents were scattered through mountainous terrain, making victory more difficult than in Germany.
  • The plan offered the only path to force a sense of utter helplessness in the Japanese.
  • The operation would be difficult but not more difficult than the Normandy invasion; there was a conviction that every individual moving to the Pacific should be indoctrinated with a firm determination to see it through.
• Admiral King’s casualty perspective:
  • King stated that a realistic casualty figure for Kyushu would lie somewhere between the numbers experienced by MacArthur in Luzon and those at Okinawa: $41{,}700$ army and navy killed, wounded, or missing.

President’s stance and Joint Chiefs of Staff (JCS) planning

• The President asked whether an invasion of Japan by white troops would tend to unite the Japanese more closely.
• Stimson’s response: there was every prospect of unity of purpose; he agreed with the JCS-proposed plan as the best path but still hoped for fruitful accomplishments through other means.
• The President’s position on the Kyushu plan:
  • He considered the Kyushu plan militarily sound and authorized the JCS to proceed with it.
  • However, he also stated that the operation could be conducted and the final action decided later, implying flexibility in overall war strategy.
• Footnote reference (as per the transcript): Ernest J. King was a fleet admiral serving as chief of naval operations and a member of the Joint Chiefs of Staff.
• Tactical emphasis: the plan emphasizes achieving military objectives while acknowledging the time needed to decide the ultimate strategic next steps after Kyushu.

Key numerical and reference points to remember

• Target date for Kyushu invasion discussion: $1\ November\ 1945$.
• Weather-related delay risk: possible delay of up to $6\ ext{months}$ ending the war.
• Luzon casualty benchmark: $31{,}000$ Americans killed, wounded, or missing.
• Okinawa casualty benchmark (for context): $41{,}700$ army and navy killed, wounded, or missing.
• First 30 days in Kyushu constraint: not to exceed the Luzon casualty cost.

Connections to broader themes and implications

• Strategic trade-offs:
  • Precision bombing vs area bombing: tension between avoiding atrocities and achieving war aims quickly.
  • Use of a new weapon (the atomic bomb) and ensuring it has a meaningful war background.
• Diplomacy and alliance dynamics:
  • The potential leverage of Soviet entry into the war as a factor influencing Japanese capitulation.
• Ethical considerations:
  • Balancing the imperatives of victory, civilian casualties, and maintaining international reputation.
• Real-world relevance:
  • This transcript sheds light on how planners weighed invasion versus continued bombardment, and when to deploy a major new weapon against Japan.

Notes on source and context

• Source documents are from high-level U.S. military planning discussions, reflecting the strategic thinking in mid-1945 as World War II in the Pacific approached its final phase.
• The document captures the interplay between military objectives, political considerations, casualty projections, and the looming question of how and when to end the war with Japan.