The escarpment dividing the High Veldt from the lowlands. Courtesy of Original Travel, UK
South Africa is a product of colonization, like most present-day southern African countries, but with a particularly complex past. The Portuguese were the first colonial power to arrive but were soon displaced by the Dutch. The British also had designs on the region, and this led to the late 19th century Boer Wars between British and Dutch colonists, in which the British were finally successful.
Outline map of South Africa showing the provinces. Drawn by htoni, released under GNU Creative Commons.
The present country is made up of four former British colonies. The original people were mostly of the Bantu language group, and the major ethnicities are the Xhosa and the Zulu, and they are considered in detail below. But there are also significant populations of Asians from the Indian sub-continent (of which Mohandas (Mahatma) Gandhi must be the most famous) and the so-called Cape Coloureds, deriving from relationships between white colonials and Africans, most of whome were imported from other African countries as slaves. In all, South Africa has 11 official languages. Zulu is the most widely spoken, followed by Xhosa, Afrikaans (Dutch) and then English. However English is the major language of commerce, science ond the media.
The original inhabitants mostly practised circumcision in the late teen years, as in Kenya, though the Zulu abandoned it in the early 19th century (see below). According to many correspondents on the old Circlist discussion group, infant circumcision is the norm among white South Africans of English descent but is uncommon among Afrikaners. South Africa once had a very large Jewish population, mostly Eastern Europeans fleeing persecution but many have since left, often to Australia. At its peak the Jewish population was about 120,000 and there were entire villages of Lithuanian jews  but as of 2018 the population was down to 67,000.
Among uncircumcised boys a non-retractable foreskin is regarded as a sign of virginity so, unlike the situation in some other African countries, boys make no attempt to retract their foreskins. That way a boy can prove that he has not had intercourse prior to his circumcision (which would be a serious blemish on his character), or in a non-circumcising tribal group, that he is a virgin prior to his marriage. Until recently this would just have seemed to be a quaint obsolete custom in modern, sophisticated South Africa, but the AIDS pandemic has made virginity testing of both boys and girls a common practice again  . However the government, which was initially slow to respond to the AIDS crisis, has been promoting circumcision extensively since 2010. The aim is for boys to be circumcised by age 10. The programme has been very successful with a million circumcisions being carried out in KwaZulu-Natal province alone by May 2018. 
The Zulu people were traditional herdsmen, like so many other south-east African tribes. Limited grazing grounds often led them into conflict with neighboring tribes, but typically casualties were slight and one group would retreat once they realized that they could not win. King Shaka (or Chaka) had other ideas. He was of royal blood, but illegitimate, and rose to power by his courage, skill and military ability. In 1816 he took over leadership of the Zulus and immediately set about creating an army that would not only subdue the neighbouring tribes but also be capable of taking on the white invaders. 
He realized that once young men were circumcised they were only interested in young women, so he banned circumcision. Young men were organized in age-groups for military service. Sex was absolutely forbidden, and punishable by death. Young women were organized in equivalent age groups, not to fight but to dance and entertain the men. Once a young man finished his military service, he would be given a wife from his age-group. Shaka also developed a new military technique. Instead of throwing spears, which would wound but not often kill, his soldiers would advance, protected by shields, until they could stab their opponents in hand-to-hand conflict. This dramatically increased the death rate, and Shaka soon dominated neighbouring tribes. However, ths tactic was less effective against white men with firearms.
Shaka's power went to his head, and he became a megalomaniac. He wouldn't have a son in case he might rise up against him so he never married. He had concubines, but once one became pregnant she was killed. This was a very short-sighted view since his half-brothers realized that it was kill or be killed and murdered Shaka after a 10-year reign. However, circumcision was still banned (but not taking wives). So it remained until recently. Facing the AIDS epidemic the current King, Goodwill Zwelithini, reversed the ban and the Crown Prince Nhlanganiso Zulu is out there promoting circumcision . BUT, the key point is that only medical circumcision performed by a registered doctor is permitted.
The Xhosa people are South Africa's second largest ethnic group. They are divided into clans, and clan affiliation is very important to them. When two Xhosa men meet they will exchange clan names before thir own names. They still have traditional leadership structures independent of the government. Young men are initiated at remote camps in the mountains. There are two 'seasons' a year, in July (winter) and December (summer). Not all follow this tradition nowadays, but it is still widely practised and regarded by many as an important part of their culture. Nelson Mandela wrote in his autobiography that he went through the circumcision ceremony aged 16. "Without a word, he took my foreskin, pulled it forward, and then, in a single motion, brought down his assegai [spear]. I felt as if fire was shooting through my veins. The pain was so intense that I buried my chin in my chest. Many seconds seemed to pass before I remembered the cry, and then I recovered and called out, 'Ndiyindoda!' [I am a man!]" . Young women also have initiation ceremonies, but they do not involve circumcision.
Xhosa initiates after circumcision, with bodies painted with white clay.
Traditionally, Xhosa boys undergo circumcision (Umkhwetha) in their remote camps, followed by a period of seclusion during which certain foods are forbidden and in which they are educated in traditional lore and undergo tests of manhood. Their bodies are painted with clay. Sadly, these 'initiation schools' now have a bad reputation with many young men dying or being left permanently mutilated. 
The causes are varied, but much can be attributed to loss of traditional practices without their being replaced by modern medical practices. Traditionally the knives used for the circumcision were required to be washed frequently but now, using modern cutting blades, they are not, transferring infections between initiates. The wound was traditionally bound up with a bandage of animal skin, which may sound primitive but had worked for centuries. Modern bandages are often put on too tight, leading to gangrene and necrosis. The huts in which the initiates are secluded where traditionally of grass, but now they are often just covered with plastic sheets in which, especially in the summer initiation season, initiates can stew, becoming seriously dehydrated. Education in tradition is often forgotten, and 'tests of manhood' often seem more like sadism. Despite this, the camps remain popular 
Much of this can be attributed to 'cowboy operators' without traditional training who see running a circumcision school as an easy source of money. A South African doctor has (in spite of threats against him) documented the problems on the Ulwaluko website . Be warned, some of the mutilation images require a strong stomach. He also proposes ways of solving the problem. Traditional leaders were initially opposed to any interference, but have now come round to working with the authorities. And it does seem that there is now some improvement. In the Eastern Cape province only 17 boys died in 2017, compared to 31 in 2016 and 46 in 2015. Even so, these are horrendous figures, remembering that deaths from conventional circumcision are way below 1 in a million. The government feels that criminal prosecutions would be appropriate in some cases.
References and Sources
Personal contributions from many members of the old Circlist discussion group.
Many of the references cited here have contributed widely to this article, beyond the actual text citations.
3. Actor Melusi Yeni is KZN’s millionth man to be circumcised. Read it on IOL 26 May 2018
5. Zulu prince urges men to ger circumcised. News24
8. Despite deaths hundreds still flock to initiation schools. Huffington Post