The conquest of the Southern Sung Dynasty in that year made it unnecessary for the Yuan Dynasty to align itself with Japan or warn against the Southern Sung Dynasty (refer to the relative paragraph described below), and further, Kublai became upset by the information brought by an escaped sailor about the execution of the envoys, particularly of Shizhong DU, who held a higher position (assistant minister of rites) than usual envoys, and consequently he planned to invade Japan again and in 1280 established the Eastern Expedition Field Headquarters to prepare for the invasion.
この年に南宋を完全征服した元は、日本との同盟や南宋への牽制の必要もなくなった（後項参照）うえ、クビライは逃げ出した水夫より使者の処刑の報を知り、特に、通常の使者よりも高位（礼部侍郎）であった杜世忠の処刑に腹を立て、日本への再度の侵攻を計画し、1280年には侵攻準備のため征東行省を設置している。