minamotos reign 

Minamoto Yoritomo established the capital of his new military government in familiar surroundings at his home town of Kamakura, Plain once governed by his great grandfather. Positioned in a pretty valley on the northeastern edge of Sagami Bay it was both easy to defend and difficult to invade. Where Taira no Kiyomori had only limited military control in the immediate area around the imperial capital at Heian-kyo, minamotos military dominance was nationwide. Kiyomori exercised his authority from behind the scenes and largely through the old civil government structure in the tradition of the Fujiwara before him. minamoto declined to dethrone the emperor and created an entirely new and separate governmental structure closely linked with the old civil administration, but independent of it and separately based Kamakura.

The post of shogun was, in theory at least, purely military, so minamoto administration and those of later military rulers came to be known as the shogunate, bakufu, or "tent government," to distinguish it from the civil government in Heian-kyo.