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Title: V [Marine] Amphibious Corps Planning for Operation Olympic and the Role of Intelligence in Support of Planning.

Author: Major Mark P. Arens, USMCR [MCIA]

CONTENTS

PREFACE.................................................................................................................iii

LIST OF FIGURES................................................................................................. vii

LIST OF MAPS..................................................................................................... ...ix

Chapter

1. UNCONDITIONAL SURRENDER......................................................................1

U.S. Strategy, 1

Decision to Invade the Homeland, 4

Operation Olympic, 6

Command Relationships, 14

2. V AMPHIBIOUS CORPS.................................................................................17

The Mission, 17

Planning, 20

The Amphibious Objective Area, 23

The Forces, 25

Concept of Operations, 27

Training and Rehearsal, 30

3. ESTIMATE OF THE ENEMY SITUATION........................................................32

Intelligence Estimate of March 1945, 32

Intelligence Estimate of April 1945, 33

V Amphibious Corps' Intelligence, 40

U.S. Intelligence Sources, Methods and Organizations, 46

4. OPERATION KETSU-GO.................................................................................53

Japanese Homeland Defense Strategy, 53

Defense of Kyushu, 58

Coastal Defenses / Fortifications, 66

Satsuma Peninsula Defenses (40th Army), 70

5. CONCLUSION..................................................................................................75

Intelligence Success of Failure?, 75

V Amphibious Corps, 79

Casualties, 82

Conclusion, 84

Appendixes

A. Chronology.......................................................................................................85

B. Key Individuals.................................................................................................88

C. U.S. Ground Force List....................................................................................90

D. Japanese Ground Force List.................................................... ......................92

Bibliography...........................................................................................................96

LIST OF FIGURES [FIGURES NOT AVAILABLE HERE - Try the original ZIPed Ami Pro file !!!]

Figure Page

1. Members present at Japanese strategy meeting of 18 June 1945..............................6

2. Major U.S. ground forces designated for Operation Olympic......................................8

3. Number of naval ships in selected WW II campaigns..................................................9

4. Organization of American forces for Operation Olympic............................................16

5. Picture of Major General Henry Schmidt ...................................................................17

6. U.S. estimate of Japanese ground forces in Southern Kyushu, April 1945................34

7. U.S. estimate of Japanese ground forces in Northern Kyushu, April 1945................36

8. U.S. estimate of Japanese ground forces on Satsuma Peninsula, July 1945............44

9. Comparison of Japanese and U.S. unit designations.................................................56

10. 16th Area Army's sub-division of Kyushu for defense planning..................................59

11. Major Japanese ground forces for Ketsu-Go..............................................................59

12. Coastal defense zones...............................................................................................67

13. Battalion position in Main Zone of Resistance............................................................69

14. Casualty ratios of selected battles in the Pacific.........................................................83

LIST OF MAPS

Map Page

1. U.S. Pacific strategy in 1945........................................................................................3

2. Operation Downfall......................................................................................................5

3. Operation Olympic scheme of maneuver, X-Day.......................................................11

4. Concept of operations after landing on X-Day...........................................................13

5. Proposed VAC landing site on Satsuma Peninsula...................................................20

6. V Amphibious Corps concept of operations...............................................................29

7. U.S. estimate of Japanese force disposition in Southern Kyushu, April 1945...........35

8. U.S. estimate of Japanese force disposition in Southern Kyushu, July 1945............42

9. Japanese estimate of U.S. invasion plans.................................................................60

10. Disposition of Japanese ground forces in southern Kyushu , August 1945 ..............71