The Yamana clan of the Inaba province, were descendants of Minamoto Yoshishige. Yoshishige's son, Minamoto Yoshinori adopted the surname of "Yamana". From that point onward, the Yamana clan became a very powerful shugo family in the Muromachi Period. The Yamana gained very much power due to that of Yamana Tokiuji, who was a very valiant retainer under the Ashikaga. Under the leadership of Yamana Michitoyo, they were at the heart of the Onin-War, which was over a decade long. In the end it costed the Yamana much of its former influence and land. The Yamana had then been reduced to holding the better part of Inaba Province around the 16th century. That erea would be retainer by the Yamana even until the end of the Edo Period. Categories: Japan geography stubs | Japan | Old provinces of Japan ... Shugo (守護) is an official post named by the Shogun, which oversees a province (kuni) in Japan. ... The Muromachi period (Japanese: 室町時代, Muromachi-jidai, also known as the Muromachi era, the Muromachi bakufu, the Ashikaga era, the Ashikaga period, or the Ashikaga bakufu) is a division of Japanese history running from approximately 1336 to 1573. ... Ashikaga (足利市; -shi) is a city located in Tochigi, Japan. ... Categories: Japan geography stubs | Japan | Old provinces of Japan ... The Edo period (Japanese: 江戸時代, Edo-jidai), also called Tokugawa period, is a division of Japanese history running from 1603 to 1867. ...