What is "roju"

The , usually translated as Elder, was one of the highest-ranking government posts under the Tokugawa shogunate of Edo period Japan. The term refers either to individual Elders, or to the Council of Elders as a whole; under the first two shoguns, there were only two Rōjū. The number was then increased to five, and later reduced to four. The Rōjū were appointed from the ranks of the fudai daimyo with domains of between 25,000 and 50,000 koku.