In 1592, Toyotomi Hideyoshi invaded Korea, intending to use it as a route to send his armies to conquer Ming China. His forces achieved early success against the Korean army, capturing Seoul. Attempting to reach Seoul as fast as possible, the Japanese forces bypassed Jeolla Province. The governor of Jeolla, Yi Gwang, decided to lead his forces against the Japanese in a counterattack.^[3]

Yongin was a Japanese communication fortress, near Suwon. It was held by the daimyo Wakisaka Yasuharu. Yi Gwang led a force of 60,000 against it.^[1]

Against Kwon Yul's warnings and advice, Yi Kwang launched an attack without making a reconnaissance. One group of the Korean army took up positions on a hill, while the other attacked the fortress itself. Wakisaka's forces counterattacked, and destroyed the Korean army through an ambush.^[2]

Many of the Korean officers were captured by the Japanese in the battle. Nevertheless, Gwon Yul and Hwang Jin retreated in good order and were able to gather surviving scattered troops for the victory at the Battle of Ichi. Thus, Jeolla remained outside Japanese control for the rest of the first Japanese invasion of Korea.

On the other hand, the defeat of Yongin (along with the defeat at the Imjin River) convinced King Seonjo to abandon Pyeongyang and evacuate to Uiju. Historian Kim Haboush describes the destruction of the Joseon relief force at Yongin as one that dashed any hopes of Joseon regaining the initiative and bringing a quick conclusion to the war.^[4]

Although the Korean troops would eventually retake Seoul after winning a decisive victory at Hangju in 1593, the Koreans would never field an army of 60,000 at one point for the remaining of the war.

The battle is repeatedly referenced in the 2022 film Hansan: Rising Dragon directed by Kim Han-min. In the movie, Japanese Commander Wakisaka Yasuharu is considered a formidable foe by Korean commanders due to his stunning victory over the numerically superior Joseon forces at Yongin.