Toyotomi Hideyoshi's campaign to bring Japan's warlords under his rule concluded in 1590 with his defeat of the Hojo clan at Odawara. With his wars at an end, he suddenly required an outlet for samurai aggression if he were to have any chance to solidify his hold over a unified Japan. An invasion of China, traversing tiny Joseon, was just what he needed both to buy time and create conquered lands, which he could then dispense to loyal retainers. Whether or not Hideyoshi really expected Joseon to defend itself remains difficult to ascertain, but it appears unlikely he considered such resistance an obstacle to his plan. It is worth noting that Hideyoshi had never before experienced naval warfare.
The kingdom of Joseon had been ruled by the Yi dynasty for nearly 200 years, a monarchy governed by strict Confucian principles. The kingdom traded extensively with Ming China under the tributary system, a natural outcome of Korea and China expelling their Mongol overlords almost simultaneously in the mid to late fourteenth century. Its
