It is often assumed that Albert Kahn developed the Kahn bar. However, it was actually his brother, Julius, who invented the bar early in the twentieth century. At the beginning of reinforced concrete construction, most of the bars used for tensile reinforcement were square, or less often round, but always plain and not deformed as bars are today. Engineers knew they had to check for bond in every selection of reinforcement to make certain that each bar was sufficiently anchored at the ends. The development of the Kahn bar was a great step forward; it consisted of a horizontal rolled section with flanges that were cut away and bent up to resist shear in beams or slabs.