EBB AND FLOW

NOVEMBER 1950 - JULY 1951

The Foundation of Freedom is the Courage of Ordinary People

History    On Line

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by
Billy C. Mossman

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

. . . to Those Who Served

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Korean War TimeLine

Korean War Photos
Other Korean War Photos of 1950
Other Korean War Photos of 1951
Korean War Photos of 1952

Main Line of Resistance (MLR) - Map and Key Battles

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Foreword

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.

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.

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

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

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 (Chosin) 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

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

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

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

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

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

Illustrations

History    On Line

Causes of the Korean Tragedy ... Failure of Leadership, Intelligence and Preparation

The Foundations of Freedom are the Courage of Ordinary People and Quality of our Arms

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