South Africa's divided black activists work toward a clenched-fist unity

Waving his hand above the crowd, Bishop Desmond Tutu demonstrated a simple but basic truth about black politics in South Africa. ''Outspread, those fingers can be easily broken,'' he said. ''But clenched into a fist they are very difficult to break.''

Black activists here are searching for a more united stand that would give them greater clout than the sum of their parts in opposing the white minority government.

Bishop Tutu of the South African Council of Churches was addressing the first meeting of a new black group called the National Forum. The forum was convened to pursue greater cooperation between black movements, now often at odds in their strategy of opposition. Some 200 black organizations were represented at the meeting June 11 and 12 in Hammanskraal, north of Pretoria.

The meeting was the latest evidence of ferment in the ranks of black activists. Other efforts are under way in the independent black trade unions and among certain political groups to overcome or at least work around the ideological and tribal differences that have been a prominent and debilitating feature of black politics in recent years.

The gathering itself may signal a new will among blacks to draw closer politically, despite differences. But the meeting also served to articulate certain fundamental disagreements among blacks that most analysts here do not feel will be quickly or easily bridged.

The organizers of the meeting saw it as a successful start of a process of unification.

Black political opinion in South Africa is divided basically into two camps. There are those who subscribe to the philosophy of ''black consciousness,'' spawned in the late 1960s and brought to prominence during the 1976 upheaval in the Johannesburg suburb of Soweto. And there are those who align themselves with the tradition of the Freedom Charter, a political manifesto adopted in 1955 by a number of groups, including the now-banned African National Congress (ANC).

The ''charterists'' advocate cooperation with those white South Africans who are committed to dismantling apartheid. Supporters of black consciousness embrace a philosophy of black pride and self-respect that sees a very limited role for whites in the ''liberation struggle.''

Bold acts of sabotage by the ANC have given it a higher profile than any black-consciousness group. There appears to be fairly broad and growing sympathy among blacks for the ANC, and a number of groups in South Africa have aligned themselves with the tradition of the Freedom Charter.

However, this is not to say that black consciousness is dead. As a political movement its influence has waned. But analysts say it has fundamentally altered the thinking and outlook of many blacks.

The catalyst for the National Forum was the government's so-called ''reform'' initiative, which blacks see as a further effort to politically divide and weaken ''nonwhites.'' That initiative, now before Parliament, would change South Africa's Constitution to bring Coloreds (persons of mixed race) and Indians into the central government, while still excluding the black majority.

The National Forum had a black consciousness orientation, but a number of ''charterist'' groups and individuals participated and endorsed its manifesto.

In an earlier uniting of black opposition to the government's ''reforms,'' a number of black groups formed a United Democratic Front. This front was more aligned with the tradition of the Freedom Charter. But some members of the United Democratic Front also participated in the new National Forum, indicating that the two are not seen as mutually exclusive efforts.

The forum adopted a manifesto that supporters of black consciousness and the Freedom Charter could both endorse. It read in part: ''Our struggle for national liberation is directed against the system of racial capitalism which holds the people of Azania (blacks' name for South Africa) in bondage for the benefit of the small minority of white capitalists and their allies, the white workers and the reactionary sections of the black middle class.''

The platform reflected one area of agreement between the two camps in black politics. That is a basic pro-socialist leaning and a view that oppression in South Africa is the product of a class struggle as well as one of racism.