Wokou, which translates to "Japanese pirates", were pirates who raided the coastlines of China and Korea from the 13th century to the 17th century. The wokou were made of various ethnicities of East Asian ancestry, which varied over time and raided the mainland from islands in the Sea of Japan and East China Sea. Wokou activity in Korea declined after the Treaty of Gyehae in 1443 but continued in Ming China and peaked during the Jiajing wokou raids in the mid-16th century. Chinese reprisals and strong clamp-downs on pirates by Japanese authorities saw the wokou disappear by the 17th century.

Korea is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, now known as the Korean Demilitarized Zone. In 1948, two states declared independence, both claiming sovereignty over all of Korea: South Korea comprising its southern half and North Korea comprising its northern half. The region consists of the Korean Peninsula, Jeju Island, and minor islands near the peninsula. The peninsula is bordered by China to the north and Russia to the northeast, across the Amnok and Duman rivers. It is separated from Japan to the southeast by the Korea Strait.