In 1587, Hideyoshi sent his first envoy Yutani Yasuhiro, to Korea, which was during the rule of King Seonjo, to re-establish diplomatic relations between Korea and Japan (broken since the Wokou raid in 1555). Hideyoshi hoped to use as a foundation to induce the Korean court to join Japan in a war against Ming China. Around May 1589, Hideyoshi's second embassy reached Korea and secured the promise of a Korean embassy to Japan in exchange for a group of Korean rebels which had taken refuge in Japan.

In 1587, Hideyoshi had ordered an ultimatum to be sent to the Joseon Dynasty to submit to Japan and participate in the conquest of China, or face the prospect of open war with Japan. In April 1590, the Korean ambassadors asked for Hideyoshi to write a reply to the Korean king, for which they waited 20 days at the port of Sakai. Upon the ambassadors' return, the Joseon court held serious discussions concerning Japan's invitation. They nonetheless pressed that a war was imminent. Some, including King Seonjo, argued that Ming should be informed about the dealings with Japan, as failure to do so could make Ming suspect Korea's allegiance, but the court finally concluded to wait further until the appropriate course of action became definite.

In the end, Hideyoshi's diplomatic negotiations did not produce the desired result with Korea. The Joseon Court approached Japan as a country inferior to Korea, and saw itself as superior according to its favored position within the Chinese tributary system. It mistakenly evaluated Hideyoshi's threats of invasions to be no better than the common wokou Japanese pirate raids. The Korean court handed to Shigenobu and Genso, Hideyoshi's third embassy, King Seonjo's letter rebuking Hideyoshi for challenging the Chinese tributary system. Hideyoshi replied with another letter, but since it was not presented by a diplomat in person as expected by custom, the court ignored it. After this denial of his second request, Hideyoshi proceeded to launch his armies against Korea in 1592.