Rokkor was a brand name used for all Chiyoda Kōgaku Seikō and later Minolta lenses between 1940 and 1980,[1] including a few which were marketed and sold by other companies like Leica. The name was derived from the name of Rokkō (六甲山), a 932 metre (3058') high mountain, which could be seen from the company's glass-making and optics factory at Mukogawa near Osaka, Japan.[1] The company's founder Kazuo Tashima wanted the name to symbolize the high quality in optics.[1]