The first bullets found 13-year-old Hector Peterson. The police gunfire coming out of the cool June morning spun the dying black youth to the earth in the Soweto housing compound, and a political era ended in South Africa.

Six months and hundreds of deaths later, blending optimism and defiance, black students have renamed the dusty crossroads near Soweto's Klipspruit River, where Peterson and three classmates were shot down that first morning, "Fresdom Square."

This symbolic gesture is intended as an audacious challenge to white power in a country where the whites have snuffed out other African uprisings in this century with surprising ease.

Another hail of police gunfire directed at unarmed Africans - at Sharpeville, in March, 1960 - ushered in a 16-year period of black despair and political paralysis before a relentless expansion of white power on the southern tip of the African continent.

That power continues to be awesome, and the 300-year-old tribe of white men and women called Afrikaners who run South Africa are unhesitatingly ready to use it to preserve their rule over Africa's most powerful, most affluent and most ostracized land.

"If the word expects from us the week-kneed attitude of abdication that they found in . . . Kenya or the Congo, they are making a grave mistake." Interior Mulder said when asked about the government's willingess to shoot it out if necessary. "We have no guilty conscience about our presence in Africa."

Physical revolution still appears to be distrant.

The police firepower and quick jailing of black students and their adult allies appears for the moment to have crushed the schoolyard rebellion that began spontaneously June 16 after the police fusillade and that has intermittently shaken the country since.

Those young activists who have not fled the country admit that they remain disorganized and lack a clear immediate strategy to force change in the harsh apartheid system of racial segregation that they set out to protest peacefully in June and now swear to topple.

But many of South Africa's most perceptive black and white citizens agree that the long night of the post. Sharpeville era has ended, that police bullets alone can no longer ward off the delayed winds of change blowing south from black Africa and that black demands for freedom are overtaking white willingness to make concessions as the dominant political force here.

For many blacks in South Africa psychological revolution is already under way, dramatically transforming the once servile and politically dormant black majority that silently acquiesced to the walls of apartheid around black aspirations.

The student demonstrations, transformed into angry racial confrontations by the police gunfire, have ignited a sense of black pride and nationalism that had been silently building behind apartheid's walls since the beginning of the decade.

"The students showed us we had no right to feel helpless, to despair and give up," says black editor Percy Qoboza.

"We're finished looking at ourselves as victims and looking up to the white man for concessions," asserts the Rev. Manas Buthelezi, another emerging black urban leader "The students aren't asking for the hurts of the system to be softened, like their parents were six years ago. They're saying the system has to go."

A student activist claiming to speak for the country's 18 million blacks, who outnumber whites four to one, puts it more simply: "It is our land. We want our land back."

Eric Dane, a young white lawyer who has handled many of the cases brought against hundreds of jailed students, noticed the change this way:

"It's funny. Their parents come in and still call me 'master,' or 'boss,' as they do any white person. The students, who know they need me if they are to get out of jail, call me 'Mr.' or 'Sir' - but never 'master.'"

The tremors of change are also shaking the white community, which is far more deeply entrenched and industrially proficient than the English, French and Portuguese colonial settlers who have been swept back out of Africa in the past two decades.

The student rebellion arrives as Cuban soldiers in Angola are facing whithe South Africa troops across an internationally disputed border, an unknown President elected with important black support is moving to the White House and the once-vibrant and booming economy here that produces much of the world's gold, diamond and uranium exports continues to drift steadily downward.

Just as they have raised the hopes and determination of the black population, the Portuguese collapse in Angola and Mozambique and these other changes have provoked new fears, backlash and a diminishing of longstanding ethnic divisions within the white community.

"Yes, South Africa has moved into the risk category now," a senior American executive based here said.The comment was partly intended to reassure, his listeners, but it proviided a striking measure of the attitude change since the euphoric days at the beginning of the decade.

"We won't put any 20-year money in here now," he confided. "But we don't worry about 5-year investments, because we're absolutely sure the police, army and border guards can hold it for that long."

The Afrikaner officials who rule the country continue to talk as if they are sure they can hold it forever. But self-doubt, which Afrikaner intellectuals used to call "a luxury we cannot afford," appears to be beginning to spread.

Afrikaners, descendants of the original Dutch settlers who landed at the Cape of Good Hope, make up 60 per cent of the white minority and have completely controlled the national government for 28 years.

The originally rural, Calvinistic Afrikaners devised apartheid in 1948 as a way to contain the African population in native reserves, except when they were needed to serve white economic needs. Apartheid has subsequently been refined into separate development, which provides black "homelands" to justify the continuing denial of meaningful political rights to blacks in white South Africa.

English-speaking whites, who began to settle in large numbers only late in the 19th Century after the discovery of gold and diamonds, form a minority within the white minority. They continue to dominate the economy, the cultural life and the enfeebled liberal opposition which once called for a multiracial society but now finds itself caught in the rising clash of African and Afrikaner nationalism.

"All we can do now is try to minimize the violence that is coming" says one disillusioned liberal.

The most important voices urging peaceful compromise with black aspiration come now, ironically, from within the increasingly urbanized and business-oriented Afrikaner community. Class structures unknown to their rural forebears are developing in the community and making some Afrikaners more flexible in their approach to race.

The Afrikaner government, headed by Prime Minister John Vorster, a plump, pugnacious man whose style of governing runs more to intimidation and bullying than to persuasion of consensus, has responded by pledging to move away from racial discrimination as official policy and has permitted some racial barriers to be dropped in the once-rigid system of segregation here.

"We were able to present a positive picture of South Africa up to a certain stage this year," Connie Mulder said in an implicit acknowledgment of the image-building aspect of the changes in some of the most familiar, and degrading, aspects of apartheid.

"Just before the riots started, all of our speeches streesed better race relations and said that people had to accept a man on his own merit," he continued. "But this has been a setback. People are asking if that wasn't mistake, and we are curbed in what we can do in the present situation. We will continue our policies, but people are asking, 'What's the use in concessions?'"

"I don't know what it was like before separate development," said a 21-year-old Afrikaner university student. "I'm too young to really remember Sharpeville. We've felt things were always in control. Now, we begin to feel that events are moving beyond Vorster's control."

These are among the major changes that strike a visitor traveling across South Africa for six weeks after a six-year absence. These changes and others will be detailed and explored in this series of articles that focus not only on the accelerating rate of change and conflict within this nation's rich mosaic of ethnic and racial groups, but also on the impact that those groups' success or failure in coexisting will have on race relations in Africa and globally.

Six years ago, white South Africa sat in isolation from the rest of the continent.

When it thought about change at all, the white community debated it in genteel terms concerning economic advancement for blacks andmoral suasion for whites. An extended examination of the country then could conclude that embryonic Afrikaner dissent to apartheid would be the determining factor in peaceful change here.

White politics' contribution to change has been eclipsed by the bloody race violence inside the country's borders, the Portuguese collapse and Vorster's disastrous involvement in Angolas, and the joint effort with the United States to get a settlement to the guerrilla war in Rhodesia - all of which have helped jolt South Africa out of that isolated and abstract situation of 1970.

The new black challenge to white power across the region has all but destroyed hope for the kind of peaceful evolution into a multiracial common society long held by leaders like the late Chief Albert Luthuli and writer Alan Paton. Some form of race warfare, a seemingly unrealisitc specter to this reporter six years ago, is suddenly a chillingly real possiblity.

Increasingly, white South Africans are concluding that their chances for long-term survival depend on American help in countering the Soviet pressure building up on their borders. Blacks also think that American involvement - on their side - would be crucial here.

The changes have already produced, in September, a visit to Vorster by an American Secretary of State. But Henry A. Kissinger's trip does not appear to have reassured the whites, and his failure to even ask to see black leaders imprisoned, restricted or boycotted by the government for political activities increased the distrust many blacks, already felt toward the United States because of the highly visible American commercial presence here and its quiet acceptance of apartheid.

"When Kissinger came here, the time of friendly family politics, of things being taken care of by our uncles and cousins in Pretoria, vanished forever," said Pieter Dirk Uys, a young Afrikaner playwright whose work is beginning to capture the feeling of a white man being trapped in the vast spaces of Africa. "Now we are in the big leagues, and it is frightening."