The son of Mozambique’s ex-president and 18 others have gone on trial over the $2bn (£1.5bn) “tuna bonds” affair.
Ndambi Guebuza, son of former President Armando Guebuza, and the others face charges of blackmail, embezzlement and money laundering.
They have not yet commented on the charges.
Mozambique’s biggest corruption scandal led donors including the IMF to cut funding for the country and the economy to collapse.
The trial is being held in a large canvas tent in the grounds of a maximum-security prison in the outskirts of the capital, Maputo.
The city’s courtrooms were deemed too small for the scores of lawyers, 70 witnesses and 250 media workers who have been accredited to attend.
In the opening court session, the judge said all the accused must attend court in prison uniform.
Although Mr Guebuza is no longer in office, his Frelimo party remains in power, as it has been since independence in 1975.