The first is that they managed to get many of their daughters to marry nobility or even the emperors themselves. This allowed them to get political power since they would become a famous and noble family since they would be in direct relation with the emperor of Japan and this meant that they could influence them through their daughters.
Another is that they served as advisers to the rulers. They were educated and wealthy and served as advisers to the emperors or other rulers, so this meant that they would create policies that they wanted and would manage to pass them through the emperor with ease since the emperor believed them and sometimes they even ruled from the shadows when the rulers were weak.
