The Army of the Republic of Vietnam, more commonly known (in Western sources) as South Vietnam's Army, South Vietnamese Army, and even QLVNCH (as an abbreviation of Quân lực Việt Nam Cộng
Ḥa, meaning Republic of Viet Nam Military Forces commonly known as South Vietnamese military). Notice here that the Army (as a Force within all the Armed Forces) gets confused with the term Military Forces, or even "military" as a whole, because of the preconceived idea that the Army encompassed all the fighitng power in combat (which up to some extent was true, but not fully, since other Forces, like the Navy, Marines and Air Force also took part in the armed conflict). On 26 October 1955, the military was reorganized by the administration of President Ngô Đ́nh Diệm who then formally established the Army of the Republic of Vietnam (ARVN) on 30 December 1955. It lasted until the occupation of the Republic of Viet Nam's capital, Saigon, on 30 April 1975 by forces of the Democratic Republic of Vietnam (also known as North Vietnam). South Vietnam was briefly ruled by a provisional government while under military occupation by North Vietnam. On 2 July 1976, North and South Vietnam were merged to form the Socialist Republic of Vietnam. All South Vietnamese Forces were merged with North Vietnamese Forces. Esteban Rivera, 13 February 2016
image located by Art, 3 February 2016 Source: Wikipedia
Army of the Republic of Viet Nam (ARVN), flag. One can find it here.
The flag is a horizontal red flag, with a yellow eagle holding two swords in each claw, pointing upwards, in the middle, surrounded by the name of the Force on top in yellow capitals ((Lục quân Việt Nam, Army of Viet Nam) and the Army motto below (Quyết chiến Quyết thắng, "Determined to Fight, Determined to Win") also in yellow capitals, surrounded by four laurel wreaths on each corner, symbolizing they were commanded by a Four-Star General (as Commander-in-Chief of the Republic of Viet Nam Military Forces, most likely a post held by the President himself or the Ministry of Defence, since only two Generals during that era ever held the rank of Four-Star General and all Forces have this pattern of having four laurel wreaths representing the rank of Đại tướng, literally "Grand General," a rank reserved only for for the Minister of National Defence and, on occasion, the Chief of the General Staff. It is based on the earlier "(The) Viet Minh/North Vietnam Flag 1941-1955" which features the same motto. Esteban Rivera, 13 February 2016
I Corps
image located by Art, 3 February 2016 Source: Wikipedia
II Corps
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III Corps
image located by Art, 3 February 2016 Source: Wikipedia
IV Corps
image located by Art, 3 February 2016 Source: Wikipedia
The flag pattern for each Army Corps flag (Vietnamese Quân kỳ) was the
Army Standard the same color background, the same color structure of
red and yellow, the four laurel wreaths and the name on top Quân lực
Việt Nam Cộng ḥa (Republic of Vietnam Military Forces), below the
name of the Unit (Quân đoàn, Corps), below the patch with the Roman
numeral of the Unit (I through IV) and a motto below (I Corps' motto
"Bến hải hùng b́nh" ; II Corps' motto "Thắng không kiêu Bại không
nản"; III Corps' motto "Chiến thắng và xây dựng""; IV Corps' motto "Tư
tháng tư cương"). Esteban Rivera, 13 February 2016
Armored Corps
image located by Art, 3 February 2016 Source: Wikipedia
Republic of Viet Nam Armoured Corps (Vietnamese: Quân lực Việt Nam
Cộng ḥa, Vietnamese Armored Cavalry Corp, VNACC). The first Armored Infantry Command was established 1 April 1955 as one of the predecessor Units of the would-be Branch. The flag is a horizontal flag diagonally split from top right to bottom left, the top being white and the bottom being blue, with the patch in the middle, and on top the inscription "Quân lực Việt Nam Cộng ḥa" and below the colloquial name "Thiết giáp Binh" (Armoured Cavalry). Esteban Rivera, 13 February 2016 Source:Wikipedia
Artillery Corps
image located by Art, 3 February 2016 Source: Wikipedia
Artillery (Republic of Vietnam Armed Forces) (Vietnamese: Pháo binh, ARVNAF). The first Artillery battery was established on 1 November 1951 as one of the predecessor Units of the would-be Branch. The flag is a horizontal flag diagonally split from top right to bottom left, the top being red and the bottom being white, with the patch in the middle, and on top the inscription "Pháo binh" (Artillery) and below the motto "Sấm sét" (Electrical storm). Esteban Rivera, 13 February 2016 Source:Wikipedia
Airborne Division
image located by Art, 3 February 2016 Source: Wikipedia
Republic of Vietnam Airborne Division (Vietnamese: Binh chủng Nhảy
Dù, Vietnamese Airborne Division, VNAD). It was established on 1 January 1948, then again established (now as part of the Republic of Viet Nam) within the Republic of Viet Nam Military Forces on 26 October (unofficially) and on 30 December 1955 (officially). The Vietnamese Airborne Division was one of the earliest components of the Republic of Vietnam's Military Forces
(Quân Đội Quốc Gia Việt Nam). The Vietnamese Airborne Division began as companies organised in 1948, prior to any agreement over armed forces in Vietnam. After the partition of Vietnam, it became a part of the Army of the Republic of Vietnam. The flag is a purple horizontal flag with the patch in the middle, and on top featuring part of the motto "Thiên thần" and below the part of the motto "Sát cộng" (something like "Armed angels in red"). Esteban Rivera, 13 February 2016 Source:Wikipedia
2nd Infantry Division
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3rd Infantry Division
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7th Infantry Division
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9th Infantry Division
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18th Infantry Division
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25th Infantry Division
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Capital Security Federation
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Capital (city) Security Federation (Vietnamese: Liên đoàn An ninh
Thủ đô). Since the whole country was split into (first) six Military Regions and then into Tactical Zones (hence the Area of Operations of each Army Corps), the capital Saigon was within the Area of Operations of III Corps, but was itself called a Special Zone in 1964. This Federation encompassed several Units that were in charge of security in the Area. It was also known as "Lực lượng Biệt khu Thủ đô" (Special Forces of the Metropolitan Area (of Saigon)). It was established on 1965. The flag is a horizontal red flag with the patch in the middle, with the inscription on top "Quân lực Việt Nam Cộng
ḥa" (Republic of Viet Nam Military Forces), below the inscription "Liên đoàn An ninh Thủ đô," below the patch and below the motto "Trung-dũng" (something like "to search").
Notice that in this classification, the term Corps is not an Army Corps (in manpower size terms) but it refers to a specialized unit, that has multiple of this specialized Units (which can be Divisions, Brigades, Battalions and/or Companies), that could have been attached during combat operations to any of the four existing Army Corps (I-IV), or even could operate independently commanded by a higher echelon (i.e. Army Operations Chief of Staff or even a higher authority given the case). Esteban Rivera, 13 February 2016 Source:Wikipedia
Rank flags for one-star through four-star generals in the Army of the Republic of Viet Nam (ARVN). Judging from the photographs I was able to find online, the flags appear to be visually similar to the same rank flags in the US Army, but flipped upside-down with the stars pointing toward the ground. Randy Young, 9 April 2016
The above two rank flags suggests that there were flags for each General Officers (Sĩ quan cấp Tướng) rank flag (from One Star to Four Star Generals). Source:Wikipedia Esteban Rivera, 13 February 2016