Date Approved


Degree Type

Open Access Senior Honors Thesis

Department or School

History and Philosophy

First Advisor

Tomoyuki Saseki


In this thesis, I examine why there were phases of intense international raiding by Japanese pirates during Japan's medieval period. The scope of the study spans two distinct phases of piratical activity by Japanese marauders known as the wako, the first lasting from 1223 to 1265 and the second from 1350 to the early 1400s. As the wako have been studied before from the perspective of the central governments of the period affected by the raiding, namely those of Japan, China, and Korea, this is an examination of the causes of piracy from the perspective of those on the periphery of Japanese society.