Volume II presents in detail the operations of the 1st Marine Division

and the 1st Marine Aircraft Wing as a part of X Corps, USA, during and immediately following the Inchon Landing on 15 September 1950.

In order to tell a complete story of this historic amphibious operation, the authors have described the mobilization of the Marine Corps reserves to form the components of the Division and Aircraft Wing; the movement to the staging area and the hurried planning for an amphibious landing; the withdrawal of the 1st Provisional Brigade and Marine Air Group 33 from the embattled Pusan Perimeter to amalgamate with the larger force for D-day at Inchon; the seizure of Seoul and its environs, and finally the withdrawal on 7 October to prepare for the Wonsan operation.

Again, this is primarily a Marine Corps story. Activities of other services are presented in sufficient detail only to set this operation in its proper perspective.

Grateful acknowledgment is made for the valuable information furnished by the scores of officers and men consulted by interview or letter and for the assistance provided by the Current History Branch of the Office of the Chief of Military History, Department of the Army.

Maps included herein were prepared by the Reproduction Section, Marine Corps Schools, Quantico, Virginia.

T. A. WORNHAM, _Major General, U. S. Marine Corps_, _Assistant Chief of Staff, G-3_.

Contents

_Page_ I The Communist Challenge 1

Authorization of Marine Brigade--First Conference on Inchon Landing--General Shepherd in Tokyo--Request for a Marine Division--America’s Force-in-Readiness-- Planning for the Pohang Landing

II The Minute Men of 1950 17

Expansion to Full Peace Strength--Mobilization of Marine Corps Reserve--The Influx at Camp Pendleton-- Embarkation of 1st Marine Division--Build-up of 7th Marine Regiment--Staff Groups Flown to Japan

III Operation Plan CHROMITE 37

Interview with General MacArthur--Conferences in Tokyo--Inception of X Corps--Final Conference on Inchon--Brigade Victory in Korea--The Marine Amphibious Mission

IV The Planning Phase 53

Working Around the Clock--X Corps Scheme of Maneuver-- Intelligence Planning for Inchon--The Landing Force Plan--Naval Gunfire and Rockets--Plans for Air Support

V Embarkation and Assault 73

Landing of 1st Marine Division--Plan to Seize Kimpo Airfield--Shipping Assigned to Marines--Movement to the Objective Area--Strikes and Bombardments--Marine Landings on GREEN Beach--The Two Harbor Islands Secured

VI Hitting the Beaches 97

The Assault Plan--Beginning the Ship-to-Shore Movement-- Seizure of Cemetery Hill--RED Beach Secured--LSTs under Enemy Fire--Fighting on Observatory Hill--1st Marines on BLUE Beach--Ending the Ship-to-Shore Movement--Seizure of the 0-1 Line

VII Securing the Beachhead 125

Supplies on RED and BLUE Beaches--Surgical Teams on the Beaches--Artillery and Tank Operations--The Attack on D-plus 1--Advance to the Force Beachhead Line-- Displacement Ashore of Division CP

VIII On to Kimpo 143

Operations on Other Korean Fronts--Landing of RCT-7 in Japan--Destruction of NKPA Tank Column--General MacArthur Visits the Front--The Drive to Kimpo Airfield--Action at 5th Marines CP--Enemy Counterattack at Kimpo

IX Marine Air Support 165

Helicopters and OYs in Support--Marine Air Units at Kimpo--Progress of Eighth Army Offensive--Division CP Displaces to Oeoso-Ri--Advance of RCT-1 to Sosa-- Reports of Enemy Build-up--Preparations for Crossing the Han

X Crossing the Han 187

Swimming Team Leads the Way--Marine LVTs Grounded in Mud--Daylight Assault Crossing by 3/5--Departure of General MacArthur--Supporting Arms of Bridgehead-- Command Ashore Assumed by X Corps

XI The Fight For Yongdungpo 205

Three Hills Taken by 1/5-Enemy Minefields Encountered-- NKPA Counterattacks of 20 September--Recapture of Hills 80 and 85--1st Marines in Position--Assault of Yongdungpo--Able Company on a Limb--Yongdungpo Secured

XII Main Line of Resistance 233

Three Hills Designated 105--RCT-7 North of the Han-- Attack Continued by RCT-5--Modified Plan of Corps Attack--Climax of the Marine Assault--The Epic of Dog Company--River Crossing of RCT-1

XIII Seoul as a Battlefield 253

Two More River Crossings--Division Attack of 25 September--Night Pursuit Ordered by Corps--Renewal of Drive Through Seoul--Entrapment of Dog Company, RCT-7--Last Fight on Hill 296--1st Marines in the Heart of Seoul--Objective Secured

XIV The Drive to Uijongbu 281

Operations of 28 September--Liberation Ceremony at Seoul--Crumbling of NKPA Resistance--RCT-7 and the Battle for Uijongbu--Last Days of Inchon-Seoul Operation--Summaries and Conclusions--MacArthur’s Report to United Nations

_Appendixes_

A Glossary of Technical Terms and Abbreviations 299

B Build-up of 1st Marine Division (Reinf) 303

C Task Organization of Marine Division for Inchon Landing 305

D Supplies and Equipment for Inchon 311

E Task Organization, Joint Task Force Seven 313

F Final Troop List of Division for the Inchon Landing 321

G Summary of Operation Orders Issued by 1st Marine Division for the Inchon-Seoul Campaign 323

H Enemy Units During the Inchon-Seoul Campaign 325

I Congratulatory Messages 329

J Casualties During the Inchon-Seoul Campaign 333

K Comments on Close Air Support Provided By 1st Marine Aircraft Wing 335

L Presidential Unit Citation 339

Bibliography 341

Index 347

Illustrations

_Photographs_

Sixteen-page sections of photographs follow pages 68 and 180.

_Maps and Sketches_

_Page_ NKPA Gains, 30 June-1 August 1950 29

Plan for Inchon Assault 68

Movements to the Objective Area 82

Seizure of Wolmi-do 89

Plan for Inchon Assault 99

Seizure of Red Beach 109

Seizure of Blue Beach 119

Marine Attacks D + 1 137

NK Counterattack Ascom City, 17 September 149

The Drive to Kimpo 154

NK Counterattack Kimpo Air Field, 18 September 162

Advance by 1st Marines, 17 September 174

Capture of Sosa by 1st Marines, 18 September 179

General Situation, 18 September 182

Han River Crossing and Seizure of Hill 125 189

Action on 19 September 207

Action on 20 September 218

Assault on Yongdungpo 224

Dike Defense--Company A, 1st Marines 230

Approaching the Enemy MLR, 5th Marines, 21 September 237

Smashing the MLR, 5th Marines, 22–24 September 242

Seoul Assault Plan 265

The Battle of Seoul 266

Action North of Seoul, 7th Marines 269

Pursuit of the NKPA and Capture of Uijongbu 288