FM 100-5
WAR DEPARTMENT FIELD SERVICE
REGULATIONS
OPERATIONS
MAY 22,1941
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A MILITARY CLASSIC REPRINT
U.S. ARMY COMMAND AND GENERAL
STAFF COLLEGE PRESSFORT LEAVENWORTH, KANSAS
1992
U.S. ARMY COMMAND AND GENERAL
STAFF COLLEGE PRESSIn 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 This manual superseded a tentative 1939 version.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
REGULATIONSOPERATIONS
Prepared under direction of the
Chief of StaffUNITED 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).
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 |
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 |
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 |