According to Korean documents related to Wa (Japan) or Wajin (Japanese people) such as Gwanggaeto Stele or "Samguk Sagi" (History of the Three Kingdoms), and "Nihonshoki" (Chronicles of Japan), Wa frequently dispatched troops to the Korean Peninsula almost at the rate of once every four years during the period from the alliance formation with Kudara in 366 to `the battle of Hakusukinoe' in 663.
広開土王碑、『三国史記』等の倭・倭人関連の朝鮮文献、『日本書紀』によれば、倭は百済と同盟した366年から「白村江の戦い（663年）」までの約300年間、ほぼ4年に1回の割合で頻繁に朝鮮半島に出兵している。