The purpose of this paper is to examine the continuous roles of ura-tone, village leaders, in order to establish that the grassroots socio-political structure of Wakasa Bay seaside villages did not change from the fifteenth to the seventeenth centuries. The first section investigates the structure of the villages in the sixteenth century. Soju, made up of ura-tone and otona, local political systems of villagers which ruled various aspects of village life, gradually developed. Each soju combined with others sharing common economic structures to form soju organizations, in order to widen their respective spheres of influence. Soju organizations were not under the direct control of sengoku-daimyo, feudal lords, in the sense that internal village problems were settled independently. The second section investigates the structure of the villages in the sixteenth century. Ura-tone and otona came to be called shoya and kumigashira in this era. However, the leaders of the villages and the people continued to settle internal disputes independently. This grassroots socio-political structure, called naisai, was the same as that which had existed since the fifteenth century. Murakata-sodo, protests against shoya, broke out when shoya which had ties with the Shogunate tried to benefit from its authority. Villagers refused to subordinate themselves totally to the Shogunate. This shows that villages were not the smallest political unit of the Shogunate, but were governed according to the general will of the villagers. In conclusion, the quasi-independent position of the seaside villages remained largely unchanged during the transition from 'medieval' to 'early modern' in Japan.