In Brazil what counts is appearance. If you look white, or white-ish, then you are white.

Even in Salvador, the capital and major slave port for nearly 300 years, where blacks make up more than 80% of the population, very few are to be found in government.

And incredibly, up until the 1970s even Salvador's carnival parade was for whites - blacks could only push the floats, not dance around them. That situation only came to an end when a group of blacks set up their own black-only Carnival group, Ile Ayie, meaning big house in Yoruba.

They also started a school to teach black children their own history - about the many slave rebellions, uprisings and quilombos (free territories) set up by runaways - usually excluded from official schoolbooks.

Slave trade

Up to eight million Africans from all over the continent were brought to Brazil between 1540 and 1850, when the traffic was stopped, although slavery was only finally abolished in 1888.

Most freed slaves were then turned out to become vagrants, homeless, jobless, penniless, while the authorities, alarmed that the majority of the population was now black or mixed race, did everything to encourage European immigration to "whiten" Brazil.

This policy lasted well into the 20th century, until the writings of influential sociologist Gilberto Freyre in the 1930s showed that the country's racial mixture could be seen in a positive light and the idea that Brazil was an example to the world in racial harmony was born.

The Portuguese arrived in Brazil 500 years ago

But in 1946 a Unesco study revealed that while most Brazilians approved of racial tolerance, in practice racial discrimination was widespread.

Fifty years later in 1999, a report by the Minority Rights Group International showed that discrimination had continued: black and mixed race Brazilians still have higher infant mortality rates, fewer years of schooling, higher rates of unemployment, and earn less for the same work.

Black men are more likely to be shot or arrested as crime suspects, and when found guilty, get longer sentences.

Yet there is no national black movement in Brazil, no open racial conflict, no apparent racial tension. Black Americans who live in Salvador say they feel much more at ease there than in the racially divided USA.

One of the reasons for this huge difference between the USA and Brazil is that while in America, race is defined by your ancestors - one drop of black blood makes you black - in Brazil what counts is appearance.

If you look white, or white-ish, then you are white. For black Brazilians it is this very blurring of racial lines that makes it so difficult to fight racism. And paradoxically, offers the chance for Brazil to become a real racial democracy, once it faces up to and takes steps to combat racism.