The Gyehae Treaty was signed in 1443 ("gyehae" is the Korean name of the year in the sexagenary cycle) between the Joseon dynasty and Sō Sadamori as a means of controlling Japanese piracy and legitimizing trade between Tsushima island and three Korean ports. It is also called Kakitsu Treaty (嘉吉条約, Kakitsu Jōyaku); 1443 is the third year of the Kakitsu era in the Japanese calendar.