Excerpts from Books and Wikipedia
"Japan's feudal era was characterized by the emergence and dominance of a ruling class of warriors, the samurai. In 1185, following the defeat of the Taira clan in the Genpei War, sung in the epic Tale of Heike, samurai Minamoto no Yoritomo was appointed shogun by Emperor Go-Toba, and Yoritomo established a base of power in Kamakura. After his death, the Hojo clan came to power as regents for the shoguns. The Zen school of Buddhism was introduced from China . . . and became popular among the samurai class. The Kamakura shogunate repelled Mongol invasions in 1274 and 1281, but was eventually overthrown by Emperor Go-Daigo. Emperor Go-Daigo was himself defeated by Ashikaga Takauji in 1336." [Wikipedia] "Between 1203 and 1242, the emperor challenges the shogunate, and the shogunate triumphs. . . . The shogunate would not take over the rule of Japan; instead, it would exist as one of two powerful cores around which Japan’s political elite traveled, in an elliptical and unstable orbit. The emperor retained his ritual importance; the cloistered emperor, his administrative authority; and the shogun at Kamakura, the power to use force. [Bauer: Renaissance, p. 211-2] Yoritomo was appointed shogun in 1192. "He is the first of a long line of military dictators to bear this title. The institution would last until 1913." [Wikipedia: Timeline of Middle Ages]