Hideyoshi TOYOTOMI who had intended to conquer Ming required through So clan who was the feudal lord of Tsushima and rendered homage and service to Hideyoshi on the occasion of the Kyushu Conquest in 1587, 'Yi Dynasty Korea's yielding allegiance to Hideyoshi and guidance for expedition to Ming.'
明の征服を企図していた豊臣秀吉は、天正15年（1587年）九州征伐に際し、臣従した対馬の領主・宗氏を通じて「李氏朝鮮の服属と明遠征の先導（征明嚮導）」を命じた。