A continuous multi-stage vertically sequenced gasification process for conversion of solid carbonaceous fuel material into clean (low tar) syngas. The process involves forming a pyrolysis residue bed having a uniform depth and width to pass raw syngas there through for an endothermic reaction, while controlling the reduction zone pressure drop, resident time and syngas flow space velocity during the endothermic reaction to form substantially tar free syngas, to reduce carbon content in the pyrolysis residue, and to reduce the temperature of raw syngas as compared to the temperature of the partial oxidation zone.