This paper examines the construction of defensive fortifications in Japan during the Tang Dynasty, specifically focusing on Itojo and Onojo, and their implications for Japan's relations with East Asia. Challenging the prevailing view that these fortifications were built only after the Battle of Baekgang, the authors argue, based on historical records and archaeological evidence, that Onojo's construction may have begun as early as AD 650. The paper analyzes the geopolitical context of these constructions, highlighting the shifting relationships between Japan, the Tang Dynasty, Silla, and Baekje, and demonstrating how Japan's defensive strategies reflected its evolving perception of regional power dynamics.

Zhuang Li, Kehua Liu