An 18th-century Chinese painting depicting a naval battle between wokou pirates and the Chinese. Wokou (), "Japanese pirates" or "dwarf pirates", were pirates who raided the coastlines of China and Korea from the 13th century to the 16th century. The wokou came from Japanese, Korean, and Chinese ethnicities 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-1500s.