A universal tie down assembly includes first and second longitudinal belts comprising reinforced webbing made from a flexible fabric material. Each belt includes a buckle end and an anchor end. The anchor end is a loop of the reinforced webbing. At least one longitudinal slot is woven into an edge of at least one of the belts. The length of the slot is at least as great as the width of the belts. The assembly includes a novel open under load buckle having a receiving part (female part) and an insertion part (male part). The buckle end of one of the belts is adjustably disposed in a belt opening of one of the insertion part and the receiving part and the buckle end of the other of the belts forms a sewn loop that loops through a belt opening of the other of the insertion part and the receiving part.