They will also be handed a second - provincial - ballot paper, still more imposing, listing up to 27 parties, including the Realists and the Cape-based Workers' International to Build the Fourth International. Before the voter walks away, a polling official will glue a sticker at the foot of each ballot paper, adding the particulars of the Inkatha Freedom Party, which consented to run only this week.
Every effort has been made to keep the system simple. The party leaders' faces are on the ballot to help those who cannot read. Any mark, not just a cross, will be accepted. But 300 years of South African history, and amendments contested in blood up to the eve of the poll, conspire to make the voting system daunting even for hardened voters and constitutional experts.
The new South Africa will have a federal structure - how federal is a matter of bitter dispute - with nine provincial assemblies and a two-house national parliament, based, as before, in Cape Town. Both national and provincial elections will employ the list system of proportional representation.
In the National Assembly, the lower but more powerful chamber of the federal parliament, there will be 400 seats. Half will be distributed according to the share of votes won by each party nationwide; the other 200 seats are split between the nine provinces according to population and divided between the parties, according to their share of the vote in that province. In the upper, more or less consultative house, the Senate, there will be 90 seats, 10 for each province. They will be distributed according to the parties' performance in the provinces.
All these decisions will flow from the 22,700,000 electors' single vote for a party on the national ballot-paper. Originally - to keep things simple with so many first-time voters - the same votes were to decide the separate elections for the provincial legislatures. The Inkatha Freedom Party and other smaller outfits complained this stacked the poll in favour of larger parties, preventing people from voting differently for national and provincial politicians. As a result, there will be a second ballot-paper for the provincial assemblies. The National Assembly will convene 10 days after the election - on 6 May - to choose the State President (almost certainly, barring accidents and assassinations, Nelson Mandela). The new president will be sworn in on 10 May - in a ceremony at which the Duke of Edinburgh will represent the Queen.
This approach distinguishes the interim South African constitution from other presidential democracies - such as the American or the French - where the president is elected directly and the legislature separately. Constitutional argument rages about whether the South African system bestows too much power on the president.
The State President will run a multi-party Government of National Unity for five years. Each party with 80 seats - or the top two parties in the poll - will nominate a Deputy President. One is certain to come from the ANC, the other from the National Party, probably Mr de Klerk. There will be a maximum of 27 ministers. A party is entitled to one cabinet portfolio for every 20 seats it wins. This should give three or four ministries to the National Party and one to Inkatha. The ANC should get the rest.
The Assembly, once in session, will have two roles. It will sit as a parliament and will act as a constitutional assembly to draw up the 'final constitution' for the new South Africa. Decisions on constitutional questions will require two thirds of members voting in favour. It is therefore critical how large the ANC landslide turns out to be next week. Recent polls put the ANC just below the 66 per cent needed to give them a free hand to amend the interim constitution.
There is an important point to note: the main parameters of the constitution have been cast in concrete through an exhaustive list of 33 constitutional principles. The first reads, movingly, given all that has gone before: 'The Constitution of South Africa shall provide for the establishment of one sovereign state, a common South African citizenship and a democratic system of government committed to achieving equality between men and women and people of all races.'
The most bitter constitutional argument revolves around the words 'one sovereign state'. Inkatha, and the white right, have fought for more power to be vested in the regions, arguing that this is the only way to accommodate the country's racial and ethnic diversity .
Under the interim constitution, the four provinces and jumble of 'homelands' in the old South Africa are replaced by nine provinces (see map). The largest, by population, will be Pretoria-Witwatersrand-Vaal (the Greater Johannesburg-Pretoria area) followed by KwaZulu-Natal. Foreign affairs, security, national police policy, university education and most broad economic issues will be the preserve of the national government.
The provinces will have some powers over cultural affairs, primary and secondary education, health services, housing, agriculture, welfare, regional planning, roads, tourism and industrial development. They will be given a fair share of national revenue and will be allowed to raise their own taxes, but only with the specific approval of the National Assembly.
The federalists complain that the national government will meddle in most of the areas allotted to the provinces, and Pretoria/Cape Town will hold all the purse-strings. By international standards, the South African system is distinctly federal. The powers given to the South African provinces are not much below those of the American States or German Lander. The limited taxation authority of the provinces is, however, a serious obstacle to provincial ambitions.