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FM 6-20: Tactical Employment
Field Artillery Field Manual, War Department, February 5, 1944
[DISCLAIMER: The following text is taken from a WWII U.S. War Department Field Manual. As with all field manuals, the text may be incomplete or inaccurate. No attempt has been made to update or correct the contents of the field manual. Any views or opinions expressed do not necessarily represent those of the website.]


Section I

32. GENERAL. For general principles of reconnaissance see FM 100-5. For detailed discussion of reconnaissance for artillery units see FM 6-100 and 6-101. Artillery reconnaissance must be—

a. Planned with a definite object in view.

b. Active, timely, and continuous.

c. Limited to the individuals and vehicles required.

d. Progressive.

e. Decentralized when time is short.

33. RECONNAISSANCE FOR POSITIONS AND OBSERVATION. Reconnaissance is generally limited to the area the artillery unit must occupy to carry out its mission. The area may be prescribed by higher artillery headquarters. During a march in the presence of the enemy, probable position areas are reconnoitered and possibilities of observation are studied.

34. ROUTE RECONNAISSANCE (FM 25-10). Route reconnaissance must precede every column, even though the march is planned and controlled by higher headquarters. The higher headquarters may furnish reconnaissance information and repair work.

35. PLANNING RECONNAISSANCE. Ground reconnaissance should be preceded by map reconnaissance. A study of the terrain from a high point overlooking the area to be reconnoitered facilitates prompt decisions and allows the remaining reconnaissance to be planned effectively.

36. TIME AVAILABLE. Under some circumstances an artillery reconnaissance may be carried on for several days, as in the preparation for an offensive on a large scale. Under other circumstances it must be completed in a few minutes, while the units are moving up to the - positions they are to occupy. When artillery must go into action quickly, delay caused by seeking a perfect position is unwarranted; reconnaissance is made for a position which will assure prompt and effective artillery support.


a. General. Except in displacements to the rear, artillery commanders habitually precede their commands to the position area.

b. Beginning of reconnaissance. During a march in the presence of the enemy; artillery personnel observe the terrain. To obtain early information of the plan of action and missions of artillery, the artillery commander keeps in close touch with the force commander and should accompany him on his reconnaissance. The artillery commander communicates his plan promptly to his subordinates, in order that their reconnaissance may be initiated as soon as practicable.

c. Extent of reconnaissance. The division artillery officer (group commander) reconnoiters for suitable battalion areas. He will rarely be able to make a detailed ground reconnaissance for battalion areas, but frequently must assign areas after an air or a map reconnaissance, supplemented by information from other sources. The battalion commander reconnoiters in greater detail to select the battery position areas and locations for other elements of the battalion. In general, the battery commander selects exact positions for the pieces and exact locations for other elements of the battery. Generally two or more of these steps are carried out concurrently. In a fast moving situation, the reconnaissance and selection of position is decentralized normally to battalion and battery commanders.

Section II


a. Observation is essential in order that field artillery may accomplish its mission of rendering continuous and close support. Supported commanders must plan their maneuvers to seize and hold terrain necessary for artillery observation. In order to render close support, field artillery observers must keep in close contact with the leading elements of the supported arm, and must dispose themselves so as to be able to locate and neutralize those hostile elements which interfere with the mission of the supported arm.

b. Artillery observation must be flexible in order to follow and support the constantly changing maneuver of our advanced elements. It should extend sufficiently deep into the hostile position to cover those areas from which fire can be delivered on our troops. Observation and adjustment of artillery fire are not confined to artillery observers. Officers and men of the supported unit often report the locations of targets and sometimes adjust fire thereon.

c. Field artillery depends primarily on forward observers in carrying out its close-support mission. Forward observers are selected from the best shots in the battalion. Liaison personnel often observe and adjust fire. Field artillery units utilize both ground and air observation to cover the entire zone of action or defensive sector to the required depth. Ground observation may be executed by forward observers, observers at battalion and battery observation posts, and sound and flash units.


a. The forward observer is one assigned to observe in the zone of action or defensive sector of a given unit and to maintain contact with that unit. The supported arm is mutually responsible for maintaining this contact. Direct-support battalions, and in most cases battalions reinforcing the fires of direct-support battalions, send out forward observers. It is desirable to send out forward observers in the ratio of one to each front-line company or similar unit. Forward observers are controlled and coordinated by the artillery liaison officer from the direct-support artillery with the infantry (cavalry) (armored) battalion. All artillery observers coming forward to observe in an infantry (cavalry) (armored) battalion zone or sector report to the artillery liaison officer with that battalion, in order to insure proper coordinated employment of all observers and to exploit all means for observation. This is essential since the liaison officer knows the local situation and where the most advanced elements of our own troops are located.

b. The forward observer has two general missions. His primary mission is to observe and adjust artillery fire on those hostile elements which interfere with the mission of the unit with which he is working. His secondary mission is to keep the artillery battalion informed of the situation. The forward observer is not attached to the supported unit. He is not restricted to the zone of action or defensive sector of the supported unit. He goes where he can obtain the observation necessary to give effective artillery support. He is not restricted to reporting only those targets which are of importance to his supported unit. He should report everything he sees exactly as he sees it. He should not try to observe the entire battlefield, but should concentrate his observation in that area of primary interest to the unit with which he is working.

40. BATTALION AND BATTERY OBSERVATION POSTS. In order to cover effectively the entire zone of action or defensive sector to the required depth, field artillery units establish observation posts. When a unit establishes more than one such observation post, coordination is accomplished by assigning a zone of observation to each. Targets reported from battalion and battery observation posts are carefully checked through the fire direction center of the direct- support battalion prior to opening fire, to insure that such fire will not endanger our advanced elements.

41. SOUND AND FLASH UNITS. Sound and flash units provide a valuable means of locating hostile installations. Such units are organic in the corps artillery but may be attached to division or lower units. (For details, see FM 6-100 and 6-120.)


a. General. Air observation is used to extend and supplement ground observation. Air observation permits reports of location of targets and adjustment of fire on targets normally defiladed from ground observers. Air observation missions for field artillery units may be performed by light airplanes organic in artillery units or by high performance units of the Army Air Forces. (See FM 6-40 for procedure in adjusting fire.)

b. Organic artillery air observation. Organic air observation for field artillery consists of a lightweight, unarmed, and unarmored airplane of slow cruising speed, operated by field artillery personnel, and capable of taking off and landing in small, unprepared fields and on roads in the vicinity of artillery command posts and firing batteries. Its primary purpose is to provide air observation of field artillery fire. A secondary purpose is to furnish oblique photography for use in the artillery and supported arms for terrain study of the zone or sector of the units involved. This airplane is vulnerable to the fire of hostile air and ground forces.

c. Artillery observation by air force units. Field artillery, especially long-range artillery, requires air observation beyond the capabilities of organic field artillery air observation. Such observation requires high performance airplanes of the Army Air Forces. The senior artillery commander submits requests to the force commander for such missions. In addition to missions of direct observation, the air force executes photographic missions for the artillery. Oblique air photographs are furnished for terrain study. Vertical air photographs are provided to facilitate survey and provide targets for firing charts.

Section III

43. ARTILLERY INTELLIGENCE. In order to locate remunerative targets, artillery units continuously seek information of the enemy by all available means. The most valuable sources of information are artillery observers, including ground, air, sound and flash, and vertical air photography. The highly organized system of observation and communications installed by the field artillery makes it an important source of intelligence. These systems afford the force commander a quick means for determining the location of both our own and enemy installations. Artillery commanders may be extremely helpful to supported commanders by keeping them informed at all times of the disposition of our own leading elements through contact with artillery forward observers and liaison officers. S-2 sections gather and evaluate information and disseminate it to subordinate, adjacent, and higher echelons. In large operations the intelligence section of the corps artillery staff is the principal unit in artillery intelligence. Its most important mission is the location of enemy artillery. The most important sources of information for the location of enemy artillery are vertical air photographs and sound and flash units.

Section IV

44. GENERAL. Liaison is established between artillery and supported units and, in some cases, between artillery units. Close contact between the supported unit and the artillery makes possible the timely transmission of requests for fire and gives the artillery the intimate knowledge of the situation which it requires for effective performance of its mission. Maintenance of liaison is the mutual responsibility of the supported and the supporting unit.

45. COMMAND LIAISON. Command liaison is accomplished by direct conference between the commander of the supporting artillery and the commander of the supported unit. Upon receipt of orders committing units to action, commanders should hold a conference to formulate a general plan of artillery support. To assure the efficient continuance of artillery support to meet the needs of the supported unit, constant liaison is maintained with the command post of the supported unit. Additional conferences between commanders are held during the progress of the action. When an artillery unit has the mission of reinforcing the fires of other artillery units, command liaison should be established by the commander of the reinforcing unit with the commanders of the reinforced units.


a. An artillery unit commander uses liaison officers to establish and maintain liaison with designated supported units or with artillery units whose fires his unit is to reinforce. A liaison officer is the personal representative of his commander with the commander of the supported or reinforced unit.

b. The primary mission of a liaison officer is to advise and assist the commander of the supported or reinforced unit in obtaining the desired supporting or reinforcing fires, and to keep his artillery commander informed of the plans, operations, and disposition of the supported or reinforced unit. He must be able to inform the supported commander of the capabilities of the artillery in delivering any fires desired and to transmit promptly to his headquarters requests for supporting fires. To enable the liaison officer to carry out his mission, the supported or reinforced unit commander must keep the liaison officer informed at all times of the location of hostile and friendly units, the scheme of maneuver, and the immediate needs of the supported or reinforced unit.

c. As a secondary mission the liaison officer adjusts the fire of his unit when necessary.

d. An artillery unit in direct support of an infantry unit sends liaison officers to all supported battalions. An artillery unit whose mission is to reinforce the fire of other artillery units sends liaison officers to each unit which it is reinforcing. Liaison officers should contact the commanders of the units with which they are to establish liaison in time to accompany the commanders on reconnaissance and secure detailed information as to specific fire missions desired by these units.

47. LIAISON SECTION (FM 6-101). A liaison section is normally provided to assist the liaison officer.

Section V

48. GENERAL. The employment of supporting fire is regulated by the needs of the supported arm in the various phases of combat. Supported unit commanders deal directly with the artillery assigned to their direct support. The supported unit commander, in making his plan of maneuver, must consider the capabilities of available artillery and the observation required by the artillery. This section deals primarily with coordination between artillery and infantry. The same general principles apply to coordination with other supported arms.


a. General. The planning of artillery support is influenced by many factors which include—

(1) Enemy situation, whether in movement, in position, or intrenched, and the amount and accuracy of information available on the location of enemy installations.

(2) Contemplated maneuver of the supported unit.

(3) Plan of supporting fire of other arms.

(4) Assistance which higher or adjacent artillery units will furnish or require.

(5) Conditions under which fire is to be delivered (observation, maps, time, and ammunition available).

b. Rapidly moving situations.

(1) The division order gives the general plan, the missions of major units, and the general artillery missions. It designates artillery units in support of particular units. The orders of the commanders of supported regiments give additional information required by the direct-support artillery, including the number of front-line battalions, their zones of action, location of regimental and battalion commanders, regions where the artillery should be prepared to fire, and method of calling for and lifting fires. When practicable, the supported commander indicates where the artillery should place its fires. He usually delegates the indication of specific locations to his battalion commanders.

(2) Based on the information outlined in (1) above, artillery commanders adopt dispositions to insure observed fire on targets as they develop and permit the artillery to furnish continuous support. Their arrangements include—

(a) Sending of liaison detachments to infantry battalions and assignment of missions to forward observers.

(b) Agreement with supported infantry commanders as to artillery support and signals for shifting artillery fires, if not already prescribed.

(c) Preparation and distribution of overlays, maps, or photographs showing the location of check concentrations and any prearranged fires in order to facilitate designation of targets by infantry commanders, liaison officers, and air and artillery observers.

c. Prearrangement of fires.

(1) Prearranged fires are employed whenever the conditions of the operation permit. In conference with the infantry regimental commander, the artillery battalion commander formulates a tentative general plan of artillery support, including general location, time, duration, and priority of fires requested by the infantry commander.

(2) Tentative plans for the close-support fires desired by the infantry battalions are made by the artillery liaison officers in conference with the infantry battalion commanders. This conference is usually preceded by a joint reconnaissance. The artillery commander must then coordinate the close-support plans with the general plan of support agreed upon by the infantry regimental commander. If the powers of the artillery are not fully exploited, the artillery commander suggests additional fires; if the artillery is unable to furnish sufficient fire to meet the requests, the infantry commander, with the assistance of the artillery commander, determines which of the fires available will contribute most to the success of the infantry operation. Details of the infantry plan sometimes must be changed to accord with the capabilities of the available artillery.

50. EXECUTING AND SHIFTING FIRE (FM 6-101). Fires may be executed and shifted by means of artillery observation (ground or air), on call or signal from the supported unit, by time schedule, or by a combination of these methods.

a. Artillery observation. Artillery observation is used whenever it is possible to secure it, either as a primary means of executing or lifting fires or as a supplement to other methods.

b. Call or signal from supported unit.

(1) Regulation of fires by call or signal from the supported unit, in conjunction with artillery observation, is suited to rapidly moving situations and those in which there is doubt as to the location of hostile elements. Fires regulated by call or signal may be either prearranged fires or fires on targets of opportunity.

(2) When time permits, fires to be delivered on call are prepared for likely locations of hostile troops. The supported unit then calls for such of these fires as are required to meet developments of the combat. Duration of these fires may be prearranged; or the lifts may be made on call.

(3) When the location of the enemy is known, groups of prearranged concentrations may be fired in a definite sequence; each lift to the next target is made at the request of the supported unit. A high degree of training of supported and supporting units is required. Otherwise confusion may result particularly if many lifts are scheduled.

(4) Requests for fire should include—

(a) Accurate location of the target.

(b) Description of the type of target and its dimensions.

(c) Location and contemplated maneuver of friendly troops, near the target.

(d) Duration of the fire.

(5) Time of ceasing fire can usually be coordinated by specifying its duration. A standard duration for all such fires may be arranged prior to the attack. In special cases the supported arm may specify one of the following:

(a) Duration and exact hour of opening.

(b) Duration, opening of fire to be upon a prearranged signal.

(c) Exact or latest hour for ceasing fire.

(d) Time of opening fire, cessation being on signal.

c. Time schedule.

(1) Fires may be lifted and advanced on a time schedule based on the estimated rate of movement of the supported troops. This method of regulating the delivery of fires requires time for preparation, and is inflexible and difficult to adjust to the maneuver of supported troops. Its employment in rapidly moving situations is limited; when favored by conditions it may be used for one or two groups of fires. The time schedule will be used more often in operations such as the early stages of attacks against hostile positions. Reinforcement of the organic division artillery and engagement of large forces on relatively narrow fronts can be expected to create conditions of poor visibility. In such cases the timetable, with provision for dealing with discrepancies between the actual and expected advance, normally becomes the principal basis for lifting fires.

(2) Only minor changes in the time schedule are practicable during the attack; when extensive revision is required, abandonment of the schedule in favor of other methods or a new schedule will usually be necessary.

(3) Schedule fires are planned in independent series to avoid tying the attack to a time schedule over a long period. Each series corresponds to a maneuver phase terminated by the capture of an objective. Execution of a new series of fires is usually begun on call.

d. Targets of opportunity. In case an important target of opportunity presents itself to an artillery unit which is engaged on prearranged fire missions, the artillery commander, in the absence of instructions, decides whether to continue his mission or attack the new target.

Section VI

51. GENERAL. Fire direction is the tactical command of one or more artillery units, for the purpose of bringing their fire to bear upon the proper targets at the proper time. The degree to which fire direction is exercised by an artillery commander depends on his knowledge of the situation and upon the degree to which operations are centralized. Subordinate commanders are permitted sufficient latitude and initiative to meet local situations promptly.

52. FIRE DIRECTION BY LARGE UNITS. Artillery commanders of units larger than a battalion control the fire power of lower units by organizing the artillery for combat; by assigning position areas; by assigning zones of fire to insure that fires may be massed on important areas; by designating specific important targets or areas to be covered by fire; by procuring and allocating ammunition; and by coordinating survey, communications, observation, and displacements. The ability of the higher artillery commanders to mass fires quickly by designating areas to be fired upon by subordinate units depends upon a well coordinated system of communications. When possible, direct communications to battalions by radio should be established. This will permit the force commander through his artillery commander to place masses of artillery fire on critical areas with the least possible delay.

53. FIRE DIRECTION WITHIN BATTALION. For the technique of controlling and maneuvering the fires of the battalion, see FM 6-101 and 6-40.

54. DISPLACEMENTS. Artillery displaces during combat in order to fire at effective ranges and to maintain continuous communication with liaison officers and forward observers. The method of displacement is such that some fire support is furnished at all times. The artillery commander temporarily reassigns the essential missions of the displacing units to units that remain in position. The time that units are out of action while displacing should be reduced to a minimum. When two or more artillery units must displace over the same route, the next higher artillery commander coordinates the movements. When artillery must displace over a route used by units of other arms, the force commander coordinates the movements. In general, direct- support artillery should have priority on roads.

a. Displacement of direct-support artillery. The displacement of direct-support artillery is coordinated with the supported unit. The artillery commander plans his displacement in conference with the supported unit commander. The supported unit's plan influences the time of displacement, the method of displacement, and the selection of the new position area.

b. Displacement of general-support artillery. The displacement of general-support artillery is coordinated with the action of the command as a whole. The unit displaces on orders of the next higher artillery commander; for example, the division artillery in general support displaces on order of the division artillery officer.

Section VII

55. REFERENCES. For principles and procedures relating to signal communications see FM 24-5. Technical manuals provide technical information on signal equipment. For details of signal communications in field artillery units see FM 6-100 and 6-101.

56. GENERAL. The commander of each field artillery unit is responsible for the establishment of signal communication within his own unit, with supported, reinforced, and attached units, and with other units as directed by higher authority.

57. RECONNAISSANCE. Artillery reconnaissance includes consideration of the means of communication to be employed.

58. AXIS OF SIGNAL COMMUNICATION. The axis of signal communication for an artillery unit follows that of the supported unit. When the commander of an artillery unit cannot designate an axis of communication, he reports each successive location of his command post to the next higher artillery commander as soon as it is selected.

59. MEANS OF COMMUNICATION. Means of communication employed by the field artillery are: radio (telephone and telegraph), wire (telephone and telegraph), messengers (airplane, motor, mounted, dismounted), visual, voice, and sound. No one means of communication is infallible. Alternate means must be provided.

a. Wire. Wire communication is established when the situation permits.' The time available and future needs for wire are governing factors. An initial wire system may be expanded by installation of additional circuits and switching centrals until the desired flexibility has been obtained. Artillery wire systems include trunk circuits between switching centrals and local circuits to observation posts, battery positions, liaison officers, elements of command posts, administrative installations, etc.

b. Radio. Radio communication is provided for essential elements of a unit and for communication between units. In general, each headquarters maintains a station in the net of the next higher headquarters. Special purpose nets are organized as required. On a functional basis, artillery radio nets are designed for command, fire direction, observation, liaison, and warnings. Radio is nonsecret. When more secret means are available, its use should be suspended except where speed of transmission is essential.

c. Messengers. Messengers are used when distances are short, when early delivery of message is not urgent, when the character of the message precludes the use of other means, to confirm messages transmitted by other means, or when other means of communication fail or are inadequate.

d. Visual. Visual communication is well suited for prearranged signals and short code groups.

e. Voice and sound. Voice is used between elements within easy voice range of each other. Sound communication is of value chiefly for alarms and for transmission of short, prearranged messages.

60. CODES AND CIPHERS. Artillery battalions and higher units are equipped with the codes and ciphers authorized for the unit of which they are a part. Extensive use is made of brevity codes. The Fire Control Code and the Meteorological Code provide brevity in transmitting and recording fire commands and meteorological data.

Section VIII

61. SCOPE. Security embraces all measures taken by a command to protect itself against annoyance, surprise, and observation by an enemy. Each commander is responsible for the security of his command. Regardless of the security measures taken by higher commanders, all artillery units must consider the probability of air and ground attack and take appropriate security measures. For general principles of security see FM 100-5; for protective measures of individuals and small units see FM 21-45.

Section IX

62. REFERENCES. See FM 100-20 for doctrine of employment of air power.

63. AIR-ARTILLERY COOPERATION. Air force operations in the battle area are planned jointly by the air force commander and the ground force commander. Air forces usually attack targets that cannot be reached by artillery. During the planning phase of air-ground operations the artillery officer of the ground force should be consulted concerning the capabilities of artillery fire. In decisive and critical phases, air forces may reinforce artillery fire. Artillery fire may be used to identify targets or to mark bomb safety lines.

64. AIR PHOTOGRAPHS. Vertical air photographs are of special importance in obtaining locations of enemy artillery. Distribution of information secured from air photographs is expedited by maintaining an artillery officer at the point where they are initially developed.

65. OBSERVATION MISSIONS. High performance airplanes of the air forces may be used to observe and adjust artillery fire, particularly long-range fire. A conference between the observer and a representative of the artillery unit concerned relative to communication and technique is usually necessary to insure success of the mission.


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