Under a starry sky and amid the blasts of 101-gun salute the South African flag was lowered tonight, and a blue and orange flag with the face of a leopard was raised in its place as six unconnected parcels of South African territory became the independent country of Bophuthatswana.

This newest African state whose capital city was a grassy field only eight months ago is the second black homeland to become independent under South Africa's internationally condemned policy of separate development, apartheid.

As with its predecessor Transkei, which became independent in October 1976, Bophuthatswana's declaration of independence is expected to fall on deaf ears in the international community and its new status to be officially recognized only by South Africa and Transkei.

Transkei and Bophuthatswana are the products of the policy of separate development or "ethnic democracy" which the ruling National Party introduced after it came to power in South Africa in 1948.

The intention is to carve from 13 per cent of South Africa's territory independent black states or homelands for each of South Africa's black ethnic groups while maintaining white rule over the remaining 87 per cent. Blacks make up 70 per cent of South Africa's population.

The new homeland is for the 21 million members of the Tswana tribe. 1.4 million of whom live outside the territory. As citizens of the new homeland they will lose their South African citizenship and political rights, one of the controversial aspects of the homelands policy.

Like a scattered jigsaw puzzle. Boputhatswana consists of six separate districts, totaling 16,000 square miles in north central South Africa. Each district is surrounded by "white areas," governed by the white minority government in Pretoria.

Two of Boputhatswana's districts border on Botswana with which it shares a common language and culture.

A vital ralway line that is the only link with the outside world for land-locked Rhodesia and Botswana passes through one of Bophuthatswana's Districts. There has been speculation that Bophuthatswana refuses to recognize the new state.

In his remarks at the midnight independence celebrations Bophuthatswana's head of sate, Chief Licas Mangope, 53, indicated that his country's unusual geographic arrangement, which he acknowledged provoked ridicule in foreign circles, would contiune to plague the "naturally strained relations with our former colonial master South Africa."

Chief Mangope told thousands of celebrating Bophuthatswana citizens that "just as it is born our independence has already fallen into a fatal creditibility gap - the territorial creditibility gap which bears the stamp "made in Pretoria." It is not at all surprising, I am afraid, that in overseas capitals they show me a map of the bits and pieces of Bophuthatswana and add the sarcastic remark, "Did you say independence? Please forgive our mirth. We thought you were joking.'"

The expected international boycott was foreshadowed by the fact that the 120 foreign and national journalist covering the two-day independence celebrations far outnumbered the few official visitors. South African Foreign Minister R. F. (Pik) Botha, Transkei's Chief Kaiser Matanzima and the leaders of two other homelands that are expected to become independent in the future were the main "foreign" dignitaries.

Critics say that the geographic and economic dependence of the homelands on South Africa precludes any true independence. For Bophuthatswana's first year of independence, 71 per cent of the $83 million budget will be grants from South Africa says >TO> the newly independent homeland is as economically viable as any other recently independent African state and that its per capital annual income of $263 is double that of Botswana's. That figure includes the incomes of 200.000 Tswanas who work outside the territory.

Bophuthatswana or "where the Tswanas meet" is home for about one-third of South Africa's 2.1 million Tswanas, the second largest black ethnic group in South Africa. The rest of Bophuthatswana's 900.000 citizens have other tribal backgrounds.

Mangope's Bophuthatswana Democratic Party won all but a handful of the country's 96-member legislative assembly seats in elections last September. Only 13 per cent of the eligible 2.1 million Tswanas voted in that election, since most of the 1.4 million Tswanas who live and work in South Africa's cities boycotted the vote to protest homeland independence and separate development.

These Tswanas consider Mangope a "sellout" to the white man's apartheid policy.

Mangope had tried to persuade the South African government to allow the Tswanas a choice between citizenship in Bophuthatswana or South Africa, but Pretoria did not budge.

About 45,000 people filled Independence Stadium on this chilly night to watch the tribal dances and gymanstics exhibitions that preceded the flag ceremony. Among them was Jacobeth, a 25-year-old typist who thought Bophuthatswana's independence was a good thing "so we can know and do what other people know and do."

There were some Tswanas who did-not agree. A black newspaper reporter named Steve said he did not accept independence," because we are South Africans.This land is ours. I don't want to see it broken into bits and oieces that will only turn to islands of poverty."

As the South African flag was lowered to South Africa's national anthem and the Bophuthatswana flag was hoisted to the new country's anthem, an Afikaner reporter said, "This is the part I don't like," seeing the flag come down and knowing that it's not yours anymore."

The stadium where the ceremony was held is next to Bophuthatswana's newly constructed Parliament building the eight-bedroom residence of Mangope and the homes of nine other Cabinet ministers. The $12.5 million complex, built over the last eight months on a dusty field, forms the governmental heart of Bophuthatswana's capital city, Mmabatho, which also will include the black township of Montshiwa just outside the white town of Mafeking.

Before independence, Bophuthatswana signed extradition and labor agreements with South Africa. The two countries also signed a nonagression pact.

Bophuthatswana's new 250-man army was trained by South African army officers, some of whom will remain in the new force as advisers.