Yamato period
During the Yamato period, Japan had intense naval interaction with the Asian continent, largely centered around diplomacy and trade with China, the Korean kingdoms, and other continental states, since at latest the beginning of the Kofun period in the 3rd century. According to a mythological account in the "Kojiki" and "Nihon Shoki", Empress Jingū is claimed to have invaded Korea in the 3rd century, and to have returned victorious after three years. Whether a Japanese political entity actually ruled a part of Korea in ancient times is debated, but considered unlikely for that time period.