FM 100-5

 
WAR DEPARTMENT
FIELD SERVICE
REGULATIONS

 

OPERATIONS

MAY 22,1941

 

 
A MILITARY CLASSIC REPRINT
U.S. ARMY COMMAND AND GENERAL
STAFF COLLEGE PRESS

FORT LEAVENWORTH, KANSAS
1992

 


U.S. ARMY COMMAND AND GENERAL
STAFF COLLEGE PRESS
In September 1991, the commandant of the U.S. Army Command and General Staff College at Fort Leavenworth authorized the establishment of the Command and General Staff College (CGSC) Press. The CGSC Press has the following missions:
  • To provide an outlet for the professional publication of monographs and book-length works on all subjects of interest to professional officers.
  • To aid in professional military education at all levels of the U.S. Army and other military services, foreign as well as domestic.
  • To promote and support the advanced study of the theory, history, and practice of the military art by professional officers and other military experts.
  • To promote and support the professional development of the CGSC faculty and faculties of other institutions of higher military education in the United States and abroad.

 


PREFACE

On 22 May 1941, the War Department published a new version of FM 100-5, Operations. This manual superseded a tentative 1939 version. The most recent official edition had been the Field Service Regulations dated 1923.

The Army of 1941 desperately needed up-to-date doctrinal guidance. The world was already engulfed in war, and the United States had begun to mobilize. Thus, the Army was eight times larger than it had been in 1939. Moreover, it had also embarked on a modernization program that affected virtually every facet of military activity.

The 1941 edition of FM 100-5 encapsulates the state of Army doctrine on the eve of America's entry inta World War II. This is the doctrine the Army took into the great Louisiana maneuvers of 1941. Later, it also guided the American soldiers through combat in places as diverse as New Guinea and Tunisia. Not until June 1944 did a new manual supersede this one.

In 1991, the Army chief of staff directed that a new series of "Louisiana maneuvers" begin in 1994. Unlike the 1941 exercises, these will involve computer simulations rather than real troops. They are intended to prevent postwar unpreparedness, whereas the 1941 maneuvers were part of a prewar mobilization. Both maneuvers, however, share the goal of enhancing the Army's readiness through the means of simulatad combat. To facilitate an understanding of the historical context underlying the 1994 maneuvers, the CGSC Press offers this reprint of the field manual that served the Army in 1941.

The 1941 version of FM 100-5 has long been recognized as a classic piece of doctrine writing, remarkable for its clarity of concept and prose. It is also a valuable historical artifact, preserving as it does the doctrinal thought of the Army at a critical juncture in history.

CHRISTOPHER R. GABEL, Ph.D.
Historian, Combat Studies Institute
U.S. Army Command and General Staff College

 


FIELD SERVICE
REGULATIONS

OPERATIONS


Prepared under direction of the
Chief of Staff

UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON: 1941


For sale by the Superintendent of Documents, Washington, D.C. - Price 35 cents

 


WAR DEPARTMENT
WASHINGTON, May 22, 1941.

FM 100-5, Field Service Regulations, Operations, is published for the information and guidance of all concerned. It contains the doctrines of leading troops in combat and tactics of the combined arms and constitutes the basis of instruction of all arms and services for field service. Additional doctrines pertaining to the defense of coast lines and landing operations on hostile shores are discussed in other manuals.

Field Service Regulations will be interpreted in the light of FM 27-10, Rules of Land Warfare. FM 100-5, Field Service Regulations, Operations, should be studied in connection with FM 100-10, Field Service Regulations, Administration, and FM 100-15, Field Service Regulations, Larger Units.

While the fundamental doctrines of combat operations are neither numerous nor complex, their application is sometimes difficult. Knowledge of these doctrines and experience in their application provide all commanders a firm basis for action in a particular situation. This knowledge and experience enable the commander to utilize the flexible organization with which he is provided to group his forces into task units most suitable for the accomplishment of his mission.

Set rules and methods must be avoided. They limit imagination and initiative which are so important in the successful prosecution of war. They provide the enemy a fixed pattern of operations which he can more easily counter.

It is a function of command to coordinate the tactics and technique of the various arms and services so as to develop in the forces employed on a given task the teamwork essential to success.

  [A. G. 062.11 (1-9-41).]
BY ORDER OF THE SECRETARY OF WAR:
        G. C. MARSHALL,
          Chief of Staff.
OFFICIAL:
  E. S. ADAMS,
  Major General,
  The Adjutant General.
DISTRIBUTION:
  R and H (10); Bn and L (5).

 

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TABLE OF CONTENTS
           
  Paragraphs Page
CHAPTER 1. ORGANIZATION.
  Territorial organization 1-6 1
  Organization of troops 7-24 2
CHAPTER 2. ARMS AND SERVICES.
  General 25-26 5
  Infantry 27-35 5
  Cavalry 36-46 6
  Field Artillery 47-68 8
  Coast Artillery Corps 59-68 10
  Air Corps 69-83 12
  Corps of Engineers 84-90 14
  Signal Corps 91-94 16
  Chemical Warfare Service 95-96 17
CHAPTER 3. LEADERSHIP. 97-111 18
CHAPTER 4. THE EXERCISE OF COMMAND.
  Doctrines of combat 112-118 22
  Command 119-126 23
  Estimate of the sitution 127-132 25
  Terrain 133-138 26
  Conduct in battle 139-144 29
  Staff 145-148 30
  Combat orders 149-159 30
  Command posts 160-168 33
  Signal communication 169-192 35
CHAPTER 5. INTELLIGENCE AND RECONNAISSANCE.
  General 193-195 40
  Information collecting agencies 195-202 40
  Organization of reconnaissance 203-213 42
  Execution of reconnaissance 214-222 44
  Transmission of information 223-232 46
CHAPTER 6. SECURITY.
  General 233-249 48
  Security against mechanized forces 250-254 50
  Security against chemicals 255-260 52
  Antiaircraft security 261-273 52
  Counterreconnaissance 274-278 55
  Counterintelligence 279-288 57
CHAPTER 7. HALTS AND SECURITY DURING HALTS.
  Halts 289-290 60
  Shelter 291-296 60
  Outposts 297-322 61
  Cavalry and mechanized outposts 323-325 66
  Security measures within shelter areas 326-333 67
CHAPTER 8. TROOP MOVEMENTS.
  General 334-343 69
  Shuttling 344-349 71
  Tactical considerations 350-373 72
  March technique 374-398 78
  Movements by rail 399-414 84
  Movements by air 415-418 88
  Security during movement 419-449 89

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  Paragraphs Page
CHAPTER 9. THE OFFENSIVE.
Section  I. General
  The objective 450-453 97
  Distribution of forces 454-460 98
  Forms of offensive action 461-473 99
  Frontages and depths 474-475 103
  Reserves 476-482 104
  Coordination 483-508 105
  II. Attack in war of movement 509-521 112
  III. Attack of an organized position
  Preliminary operations 522-526 116
  Preparations for attack 527-534 117
  Conduct of the attack 535-552 120
  The assault 553 125
  Continuation of the attack 554-560 125
  Reliefs to continue the attack 561-572 127
  IV. Attack from the defensive
  Planned defensive-offensive 573-575 130
  The counteroffensive 576-577 131
  V. Pursuit 578-590 131
  VI. Security in the offensive 591-594 135
  VII. Termination of offensive action 595-596 136
CHAPTER 10. THE DEFENSIVE.
Section  I. Organization for defense
  General 597-598 137
  Reconnaissance and selection of position 599-609 137
  Tactical organization 610-626 141
  Organization of fire 627-633 145
  Organlzation of the ground 634-649 148
  II. Conduct of the defense 650-671 152
  III. Termination of the defense 672-673 158
  IV. Security in the defense 674-678 159
  V. Antimechanized defense 679-695 160
CHAPTER 11. RETROGRADE MOVEMENTS.
  General 696-702 165
  Withdrawal from action 703-724 166
  Retirement 725-742 170
  Security during retirement 743-751 174
  Delaying action 752-773 176
CHAPTER 12. SPECIAL OPERATIONS.
Section  I. Attack of a fortified locality
  General 774-776 182
  Preparation and preliminary operations 777-794 183
  The break-through 795-808 188
  II. Operations at river lines
  General 809-811 192
  Attack to force crossings 812-842 193
  Defense against crossings 843-855 200
  III. Night combat 856-875 204
  IV. Combat in towns 876-884 209
  V. Combat in woods 885-893 211
  VI. Mountain operations
  General 894-908 213
  Reconnaissance 909 217
  Marches 910-914 217

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  Paragraphs Page
  Offensive combat 915-923 219
  Defensive operations 924-934 222
  VII. Combat in snow and extreme cold
  General 935-946 225
  Conduct of operations 947-973 227
  VIII. Combat at defiles 974-978 233
  IX. Jungle operations 979-984 235
  X. Desert operations 985-989 237
  XI. Partisan warfare
  General 990-995 238
CHAPTER 13. TROOPS TRANSPORTED BY AIR.
  General 996-1002 241
  Missions 1003-1004 242
  Planning operations 1005-1015 243
  Conduct of operations 1016-1023 245
  Countermeasures 1024-1029 247
CHAPTER 14. AIR TASK FORCES. 1030-1042 249
CHAPTER 15. THE DIVISION.
Section  I. Infantry division 1043-1049 253
  II. Motorized division 1050-1054 255
  III. Cavalry division 1055-1069 257
  IV. Armored division
  Organization 1070-1087 263
  Reconnaissance 1088-1089 266
  Security 1090-1099 266
  Marches 1100-1101 268
  Offensive operations 1102-1139 269
  Defensive operations 1140-1144 276
CHAPTER 16. GHQ TANK UNITS. 1145-1151 278
Index. 281

 

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Transcribed and formatted for HTML by Jerry Holden for the HyperWar Foundation