Amnesties can also be granted on special occasions. The last time this happened was in 1993 when King Boudewijn chose to celebrate the Belgian presidency of the European Union by lopping six months off the gaol sentence of each and every prisoner in the kingdom.
The king also has the opportunity to grant sentence reduction to individual prisoners. Last year 950 applications were made, but only 100 prisoners had their sentence cut. It's unclear whether Belgium's monarch will choose to grant mercy in this way.