Pentomic refers to a structure for infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

 divisions adopted by the U.S. Army in 1957 in response to the perceived threat posed by tactical nuclear weapons use on the battlefield.

"Pentomic Division" was "a public relations term designed to combine the concept of five subordinate units ('penta') with the idea of a division that could function on an atomic or nonatomic battlefield."


The official name of this structure was ROCID—Reorganization of the Current Infantry Division. However, it was generally known as the Pentomic Division. The Pentomic structure was a reaction to the perceived threat of Atomic weapons on the modern battlefield and a chance for the Army to secure additional funding.

Previously the US Army had fought World War I with the "square" organisation, every unit having four subunits. Prior to American participation in the Second World War the organisation was changed to "triangular"; with every unit generally having three subunits.

The standard infantry division was seen as being too clumsy in its fixed organization. Units were organized in a system of "5's". A division was organized with five "battle groups", each commanded by a colonel. Each battle group consisted of five line (rifle) companies, a combat support company, and a Headquarters company. Each company was commanded by a captain. Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

 battalions were organized with five batteries—four were howitzer
A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

s, the fifth was a mortar battery. The addition of "Davy Crockett" rockets with atomic warheads brought the army into the atomic age.

The pentomic division very closely resembled the wartime 82nd and 101st Airborne Divisions which had each fought with five parachute or glider
Military glider
Military gliders have been used by the military of various countries for carrying troops and heavy equipment to a combat zone, mainly during the Second World War. These engineless aircraft were towed into the air and most of the way to their target by military transport planes, e.g...

 infantry regiments. Their regiments were smaller and more austere than the regular infantry regiments of the infantry divisions. This was no accident as the top leaders of the army at this time were all airborne
Airborne forces
Airborne forces are military units, usually light infantry, set up to be moved by aircraft and 'dropped' into battle. Thus they can be placed behind enemy lines, and have an ability to deploy almost anywhere with little warning...

Matthew Ridgway
Matthew Bunker Ridgway was a United States Army General. He held several major commands and was most famous for resurrecting the United Nations war effort during the Korean War. Several historians have credited Ridgway for turning around the war in favor of the UN side...

, Taylor, and Gavin
James M. Gavin
James Maurice "Jumpin' Jim" Gavin was a prominent Lieutenant General in the United States Army during World War II...

. The armored divisions were not affected as their three combat commands
Combat command
A Combat Command was a combined-arms military organization of comparable size to a brigade or regiment employed by armored forces of the U.S. Army from 1942 until 1963...

 were considered appropriate for the nuclear battlefield.

Lineages & honors

When the U.S. Army division was reorganized under the Pentomic structure in 1957, the traditional regimental organization employed by the Army was to be eliminated. This raised questions as to what the new units were to be called, how they were to be numbered, and what their relationship to former organizations was to be. Many of the Army's senior officers were determined to perpetuate the historic lineages of the Army, unlike the situation after the Civil War when the Grand Army of the Republic
Grand Army of the Republic
The Grand Army of the Republic was a fraternal organization composed of veterans of the Union Army, US Navy, US Marines and US Revenue Cutter Service who served in the American Civil War. Founded in 1866 in Decatur, Illinois, it was dissolved in 1956 when its last member died...

 persuaded Congress to forbid the linkage between the Civil War era Union Army Corps and the new Corps organized for the Spanish American War.

On January 24, 1957 the Secretary of the Army approved the CARS
U.S. Army Combat Arms Regimental System
The Combat Arms Regimental System , was the method of assigning unit designations to units of the five combat arms of the United States Army from 1957 to 1981. CARS was superseded by the U.S...

 concept, as devised by the Deputy Chief of Staff for Personnel, which was designed to provide a flexible regimental structure that would permit perpetuation of unit history and tradition in the new tactical organization of divisions, without restricting the organizational trends of the future.

Separate brigades were organized with two or three battle groups. The 2nd Infantry Brigade was organized as follows:
  • Headquarters & Headquarters Company
  • 1st Battle Group, 4th Infantry
  • 2nd Battle Group, 60th Infantry
  • 1st Battalion, 76th Artillery
  • Company F, 34th Armor
    34th Armor Regiment (United States)
    The 34th Armor Regiment is an armored regiment of the United States Army formed in 1941.-Lineage:Constituted 28 August 1941 in the Regular Army as the 34th Armored Regiment and assigned to the 5th Armored Division...

  • Company G, 34th Armor
  • Brigade Trains
  • ??th Engineer Company
  • ??th Engineer Company
  • Troop F, 5th Cavalry


The Pentomic systems was found to be flawed in several ways.
  • Training: Officers would command with long periods of time between assignments to maneuver units. This would erode the experience and competence of Battle Group commanders once the experienced officers of World War II and Korea retired.
  • Span of control: Most people are capable of managing 2–5 separate elements. The pentomic battle group contained seven companies and in combat would habitually have 2–4 more attached such as engineers, artillery, or armor.
  • Loss of regimental cohesion: Traditional infantry regiments had long histories and commanded strong loyalty from their assigned soldiers. The Battle Groups, and later, the ROAD brigades, combined infantry battalions from different regiments in a chaotic fashion that eliminated regimental cohesion.
  • Loss of a level of command: Previously there had been Company Commanders (Captain), Battalion Commanders (Major or Lieutenant Colonel), and Regimental Commanders (Colonel); the Pentomic structure eliminated the level of Battalion Commander.

End of ROCID

In December 1960, the Army began studying proposals to reorganize again. This led to the ROAD (Reorganization Objective Army Division) initiative by 1963. The Australian Army
Australian Army
The Australian Army is Australia's military land force. It is part of the Australian Defence Force along with the Royal Australian Navy and the Royal Australian Air Force. While the Chief of Defence commands the Australian Defence Force , the Army is commanded by the Chief of Army...

 implemented a similar structure, called the Pentropic organisation
Pentropic organisation
The Pentropic organisation was a military organisation used by the Australian Army between 1960 and 1965. It was based on the United States Army's pentomic organisation and involved reorganising most of the Army's combat units into units based on five elements, rather than the previous three or...

, between 1960 and 1965 but reverted to its previous structure after experiencing difficulties similar to those experienced by the U.S. Army. The New Zealand Army
New Zealand Army
The New Zealand Army , is the land component of the New Zealand Defence Force and comprises around 4,500 Regular Force personnel, 2,000 Territorial Force personnel and 500 civilians. Formerly the New Zealand Military Forces, the current name was adopted around 1946...

 planned to reorganize its forces around a derivative of the Australian concept, but the Australians abandoned the concept before the New Zealanders could start the change. The West German Army attempted reorganization around the pentomic structure in 1957, abandoning the idea in a few years.

See also

  • Combat command
    Combat command
    A Combat Command was a combined-arms military organization of comparable size to a brigade or regiment employed by armored forces of the U.S. Army from 1942 until 1963...

  • Regimental combat team
    Regimental combat team
    A regimental combat team was a provisional major infantry unit of the United States Army during the World War II and the Korean War, and of the U.S. Marine Corps to the present day...

  • Transformation of the United States Army
    Transformation of the United States Army
    Army Transformation describes the future-concept of the United States Army's plan of modernization. Transformation is a generalized term for the integration of new concepts, organizations, and technology within the armed forces of the United States....

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.