UNITED STATES ARMY IN THE KOREAN WAR

EBB AND FLOW
NOVEMBER 1950-JULY 1951

by
Billy C. Mossman

Center of Military History

CENTER OF MILITARY HISTORY
UNITED STATES ARMY
WASHINGTON, D.C., 1990

For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402


UNITED STATES ARMY IN THE KOREAN WAR

Advisory Committee
(As of 8 September 1988)

Charles P. Roland
University of Kentucky

David B. Miller
City Hall
Scranton, Pa. 18503

Maj. Gen. Robert H. Buker
Deputy Surgeon General, U.S.A. 

Jamie W. Moore
The Citadel

Edward M. Coffman
University of Wisconsin

Brig. Gen. Stephen Silvasy, Jr.
U.S. Army War College

Brig. Gen. Roy K. Flint
U.S. Military Academy

Maj. Gen. Gordon R. Sullivan
U.S. Army Command and General Staff College

Maj. Gen. Raymond E. Haddock
U.S. Army Training and
Doctrine Command   

Russell F. Weigley
Temple University

L. Eugene Hedberg
H.D. Reid Foundation

Don W. Wilson
National Archives and Records Administration

Ernest R. May
Harvard University

 

U.S. Army Center of Military History

Brig. Gen. William A. Stofft, Chief of Military History

Acting Chief Historian
Morris J. MacGregor, Jr.
Chief, Histories Division
Lt. Col. Richard O. Perry
Editor in Chief
John W. Elsberg

iii

. . . to Those Who Served


Foreword

This volume completes the general survey of combat operations in Korea that began with the publication in 1960 of Roy Appleman's South to the Naktong, North to the Yalu. It will be followed by a study of theater logistics and an order of battle which, along with the recently published Medics' War, will comprise the series of official Army histories of America's so-called forgotten war.

Ebb and Flow records an important chapter in the Korean War. It begins with the last weeks of the pell-mell rush of United Nations forces to the Chinese border and goes on to describe in great detail the test of American military leadership and resources posed by the taxing retreat of the Eighth Army and X Corps across the frozen wastes of North Korea. It also examines the special problems posed to a fighting army during the deadly months of stalemate in the summer of 1951.

The part of the war described in this volume raises many questions for the military strategist and provides a treasure trove of lessons for the student of the art of war. The book emphasizes the limitations imposed by terrain and weather on the fighting capabilities of an American army facing surprise attack from a large, disciplined enemy. The operations it describes to such careful detail will help vivify the principles of war for those who would study the profession of arms.

It seems particularly appropriate that this volume is going to the printer during a year when the Army is emphasizing the theme of training. It is important to study carefully such a recent and important example of an American army performing superbly against great odds. I encourage the military student and veteran alike to take advantage of the insights into our profession imparted in the pages that follow.

Washington, D.C.
8 September 1988

WILLIAM A. STOFFT
Brigadier General, USA
Chief of Military History

vii

The Author

A graduate of Wayne State (Nebraska) College, Billy C. Mossman is the author of studies and monographs on U.S. Army operations in the Korean War and of two chapters, "Peace Becomes Cold War, 1945-50," and "The Korean War, 1950-53," in American Military History, a volume in the Army Historical Series. He contributed to Origins, History, and Accomplishments of the U.S. Army Reserve, published by the Historical Evaluation and Research Organization, and to Challenge and Response in Internal Conflict, published by the Center for Research in Social Systems, American University. He is also coauthor of The Last Salute: Civil and Military Funerals, 1921-1969.During World War II, Mr. Mossman served as a platoon leader with the 381st Infantry, 96th Infantry Division, and participated in the Leyte and Okinawa campaigns in the Pacific theater. In the Korean War, he was a military historian with the Eighth Army; Army Forces, Far East; and United Nations Command Military Armistice Commission. Mr. Mossman joined the Office of the Chief of Military History as an Army officer in 1954 and became a civilian staff member in 1957. As a civilian staff member, he served successively as historian, deputy branch chief, branch chief, and acting division chief. He retired in 1983 but remains active in the field of military history.

viii

Preface

This book describes military operations during the Korean War from late November 1950 to early July 1951, a period in which battle lines did indeed ebb and flow in pronounced surges. The volume is one of several in the United States Army in the Korean War series. In its coverage of combat operations, the book falls in the series between South to the Naktong, North to the Yalu by Roy E. Appleman and Truce Tent and Fighting Front by Walter G. Hermes.In describing the large-scale engagements that occurred between sizable opposing forces over seven months' time, I had to focus treatment of the battles at a somewhat high level, often corps or army. I also had to be selective in the use of detail. While this approach does not fully record the gallantry, suffering, and achievements of individual men in combat, I hope that the battle descriptions clearly indicate the substantial measure of their individual accomplishments and valor. I wrote this book over many years, interrupting my work on numerous occasions and for long periods to carry out other responsibilities and assignments. In fact, I gave the account its final touches after I retired from the Center of Military History. It was also in retirement that I designed the maps and selected the photographs that illustrate the book. During the years spent writing the book, I received valuable support and assistance from many people. Supervisory officials at all levels provided unfailing support. The successive Chiefs of Military History included Brig. Gen. James A. Norell, Brig. Gen. William H. Harris, Brig. Gen. Hal C. Pattison, Brig. Gen. James L. Collins, Jr., and Brig. Gen. William A. Stofft. Holding the post of Chief Historian during the period of preparation were Dr. Stetson Conn, Dr. Maurice Matloff, and Dr. David Trask. I received valuable assistance and guidance from a considerable number of officers who served as Chief, Histories Division: Lt. Col. James C. Griffin; Col. Louis G. Mendez, Jr.; Col. Paul P. Hinkley; Col. Leonard G. Robinson; Col. Albert W. Jones; Col. John E. Jessup, Jr.; Col. James W. Dunn; and Lt. Col. Richard O. Perry. Wise counsel also came from my branch chiefs: Charles B. MacDonald, Robert Ross Smith, Robert W. Coakley, and Walter G. Hermes. Over the course of my research, Hannah M. Zeidlik, currently the Chief, Historical Resources Branch, was a mainstay in obtaining and

ix

providing essential records, studies, and reports. On the production level, Joyce W. Hardyman performed the main editing of the volume assisted by James W. Grandy. Also importantly involved in the production process were John W. Elsberg, the current Editor in Chief, Barbara H. Gilbert, and Rae T. Panella. Arthur S. Hardyman and Linda M. Cajka processed the maps from layout to final form. Howell C. Brewer handled the acquisition and preparation of the photographs that illustrate the volume.

Notwithstanding the significant contributions of the persons named above, I alone am responsible for the interpretations made and conclusions drawn in this book and for any deficiencies that it may have.

8 September 1988
Washington, D.C.
BILLY C. MOSSMAN

x

Contents

Chapter

Page

I. THE MISSION

3

The Battleground

3

The Initial Mission

7

The Mission Expanded

17

The Mission Reconsidered

21

II. THE FORCES AND THE PLANS

23

The United Nations Command

23

The UNC Plan of Advance

42

The Outlook for Victory

49

III. THE ENEMY

51

The North Korean Armed Forces

51

The Chinese People's Volunteers

52

IV. THE BATTLE OF THE CH'ONGCH'ON

61

The Advance to Contact

61

The Chinese Attack

65

The Second Phase Offensive

72

The Threat of Envelopment

76

V. THE BATTLE OF THE CHANGJIN RESERVOIR

84

X Corps Dispositions, 26 November

84

The Advance Toward Mup'yong-ni

88

The IX Army Group Attacks

90

The Attacks Widen

98

The Tokyo Conference

103

VI. DISENGAGEMENT IN THE WEST

105

The Threat of Envelopment

105

The Second Disengagement

109

Trouble on the Lines of Communication

114

The Sukch'on-Sunch'on-Songch'on Line

116

The Roadblock Below Kunu-ri

119


xi

VII. CONCENTRATION AT HUNGNAM
128

New X Corps Orders

128

Shaping the Hamhung-Hungnam Defense

130

Concentration at Hagaru-ri

131

Withdrawal From the Reservoir

137

VIII. REDEPLOYMENT SOUTH

149

The Eighth Army Leaves North Korea

149

The X Corps Evacuates Hungnam

165

IX. THE CHINESE THIRD PHASE OFFENSIVE: THE OPENING
177

Ridgway Takes Command

177

Defensive Preparations

184

The Opening Enemy Assaults

188

X. WITHDRAWAL FROM SEOUL

192

To the Seoul Bridgehead

192

The Outlook, 2 January

195

The Evacuation of Seoul

198

XI. WITHDRAWAL TO LINE D

209

Withdrawal From the Han

210

Wonju and Hill 247

216

East of Route 29

223

XII. RECONNAISSANCE IN FORCE

228

The Problem of Motivation

228

Allies From North Korea

229

The Evacuation Issue Resolved

230

Operation Wolfhound

237

Task Force Johnson

239

Operation Thunderbolt

240

XIII. ADVANCE TO THE HAN

248

Roundup Preparations

248

Thunderbolt Continued

252

Operation Roundup

258

The Newest Army Estimate

263

XIV. THE BATTLE FOR HOENGSONG

266

The ROK 8th Division Destroyed

266

xii

Support Force 21

269

From the Road Junction to Hoengsong

272

The Costs

279

XV. DEFENDING THE WONJU LINE

282

The X Corps Position, 13 February

282

The West Shoulder, 13-14 February

285

The East Shoulder, 14-18 February

291

Chip'yong-ni and Task Force Crombez

295

A Turning Point

300

XVI. THE KILLER OPERATION

301

The Concept

301

Intelligence Problems

302

The Plans

305

The Advance

307

The Ripper Concept

310

XVII. OPERATION RIPPER

315

The Plan

315

The Advance to Line Albany

321

The Enemy Buildup

322

Hongch'on Cleared

327

Seoul Retaken

328

Ch'unch'on Captured

330

On the Eastern Front

333

The Courageous Concept

334

XVIII. ADVANCE TO THE PARALLEL

335

Operation Courageous

335

Ripper Concluded

343

The Parallel Question

344

The Rugged and Dauntless Concept

347

XIX. OPERATION RUGGED

351

The Enemy Situation

351

The Advance to Line Kansas

353

Change of Command

362

XX. TOWARD THE IRON TRIANGLE

368

The Enemy's Conspicuous Absence, 11-20 April

369

One Day's Notice

375

xiii

XXI. THE CHINESE SPRING OFFENSIVE: THE OPENING

378

The Enemy Plan

378

Panic at the IX Corps Left

381

Below Ch'orwon and Kumhwa

384

Along the Imjin

385

Adjusting the Line

389

XXII. THE CHINESE SPRING OFFENSIVE: ON THE CENTRAL AND EASTERN FRONTS
398

Attack on the Pendleton Line

398

Inje Falls

399

Repeat Performance

401

Censure

407

XXIII. THE CHINESE SPRING OFFENSIVE: ON THE WESTERN FRONT
410

Defending the Kansas Line

410

Withdrawal to Line Delta

419

XXIV. THE CHINESE SPRING OFFENSIVE: BATTLE FOR SEOUL
430

XXV. BATTLE BELOW THE SOYANG

438

The Search for the Enemy

439

The Offensive Resumed

444

The Battle Shifts East

460

XXVI. THE COUNTEROFFENSIVE

465

Stabilizing the Line

466

Counterattack

470

XXVII. SUBSTITUTE FOR VICTORY

488

Ridgway's Mission Redefined

488

Operation Piledriver

491

Armistice Negotiations: The Search for a Beginning

494

The Question of Future Operations

497

Negotiations Begin

499

The New Dimensions of Battle

502

BIBLIOGRAPHICAL NOTE

507

xiv

LIST OF ABBREVIATIONS

511

BASIC MILITARY MAP SYMBOLS

513

Tables

1. Major North Korean People's Army Units, 23 November 1950

52

2. Major Chinese Units in Korea, 23 November 1950

54

3. X Corps Battle Casualties, 27 November-10 December 1950

147

4. Losses by Major Unit, 11-13 February 1951

279

Charts

1. Theater Lines of Command for Operations in Korea, 23 November 1950

26

2. Organization of UNC Ground Forces in Korea, 23 November 1950

29

3. Organization for UNC Air Operations in Korea, 23 November 1950

40

4. Organization for UNC Naval Operations in Korea, 23 November 1950

42

5. Enemy Lines of Command, 23 November 1950

57

Maps

1. East Central Asia

4

2. Korea

6

3. The Battlefront, 23 November 1950

46

4. Battle of the Ch'ongch'on, 25-28 November 1950

66

5. The X Corps Zone, 26 November 1950

85

6. 5th and 7th Marines at Yudam-ni, 27 November 1950

91

7. The 31st RCT East of the Reservoir, 27 November 1950

93

8. Battle of the Changjin Reservoir, 27-29 November 1950

95

9. Battle of the Ch'ongch'on, 28 November-1 December 1950

106

10. The 2d Infantry Division at Kunu-ri, 29-30 November 1950

110

11. Concentration at Hagaru-ri, 1-4 December 1950

133

12. Withdrawal From the Reservoir, 6-11 December 1950

144

13. Eighth Army Withdrawal, 1-23 December 1950

152

14. X Corps Evacuation Plan

168

xv

15. Enemy Third Phase Offensive, the Opening Effort, 26 December 1950-1 January 1951

181

16. Withdrawal to Line D, I and X Corps, 4-7 January 1951

215

17. NK II Corps and V Corps Attacks, 7-22 January 1951

218

18. Operation THUNDERBOLT, 25-31 January 1951

241

19. Operation ROUNDUP, the X Corps Plan, 4 February 1951

250

20. Operation THUNDERBOLT, 1-11 February 1951

253

21. Operation ROUNDUP, 5-11 February 1951

260

22. Battle for Hoengsong, 11-13 February 1951

267

23. Chip'yong-ni, 13-14 February 1951

286

24. Defending the Wonju Line, 13-18 February 1951

289

25. Operation KILLER, 20 February-6 March 1951

303

26. Operation RIPPER, Western Front, 6-31 March 1951

316

27. Operation RIPPER, Eastern Front, 6-31 March 1951

318

28. Operation COURAGEOUS, 22-28 March 1951

336

29. The RUGGED and DAUNTLESS Operations, Western Front, 1-22 April 1951

354

30. The RUGGED and DAUNTLESS Operations, Eastern Front, 1-22 April 1951

357

31. Hwach'on Dam, 9-11 April 1951

363

32. The Chinese Spring Offensive, the Main Effort, 22-30 April 1951

380

33. The Eastern Front, 22-24 April 1951

390

34. The British 29th Brigade Sector, 25 April 1951

423

35. Battle Below the Soyang, 16-20 May 1951

446

36. 38th Infantry and Task Force Zebra Positions, 16 May 1951

449

37. Eighth Army Advance, 20 May-1 July 1951

471


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