In December 1596, negotiations between the Ming Dynasty and Japan broke down, and Toyotomi Hideyoshi re-formulated his plans for invasion after four years of stagnation. In February of the following year (the first month of the 25th year of the Ming Dynasty), Toyotomi Hideyoshi launched the Second War against Korea. With 141,490 troops and 22,100 sailors, the army invaded Korea again. This time, the coming was more menacing and the preparations were more adequate. After Emperor Shinjong received the news, he knew that the envoys and the military department had not reported the true intentions of the Japanese side to the imperial court, and they were bent on seeking peace and trying their best to deceive. Immediately furious, he immediately ordered the dismissal of Shangshu Shixing and others from their posts, and ordered Xing Jie to serve as the governor of Bingbu Shangshu, and Yushi Yanghao once again sent troops to aid Korea after taking advantage of the Military Affairs of Korea.
Lee was in trouble because of the accusations against Lee Soon-chan by the Korean general Won-kyun and the conspiracy of the Japanese double agent Yoshihara. He always resented Li Shunchen's position higher than his own Yuan Jun, and not only deliberately revoked many of Li Shunchen's orders, but also often falsely reported the naval situation and achievements to the imperial court. To denigrate Li Shunchen's personality. As a result, the imperial court became increasingly suspicious of the loyalty of the Shenwu Navy.
But the Japanese knew that if their new invasion plan was to succeed, they would first need to eliminate the man who had ruined all their previous plans. To this end, they drew up a plan to make him lose faith with the emperor. A Japanese soldier named Yoshihara was sent to the camp of North Korean General Kim Young-so, who offered to serve as an intelligence officer for the Koreans. General Kim readily agreed that Yoshihara could act as a whistleblower and provide seemingly valuable information to South Koreans. One day, he reported to General Kim: "Soon, General Kiyomasa Kato of Japan will arrive in Korea. I will soon be able to provide you with full details about the exact time and vessel of his voyage, but in the meantime, let North Korea send Thongjesa to ambush him.
General Jin believed him and asked the emperor for permission to send Li Shunchen to the enemy's arrival. The emperor agreed to the request and ordered Li Shunchen to send ships. However, Li Shunchen found himself unable to obey the emperor's orders, because he knew that the designated location was very dangerous, with many submerged reefs. Attempting any form of military action in such a complex situation would be an act of self-destruction. When General Jin learned of this, he reported it to the imperial court, and the emperor was furious, believing that Li Shunchen was disrespectful to resist the will. Lee Shun-chan was arrested and imprisoned in Seoul, where he was beaten and tortured. The emperor wanted to execute him, but Li Shunchen's prestige in the imperial court was still relatively high, and those who supported him interceded for him, so they spared Li Shunchen and exempted him from the death penalty.
As Yuan Jun wished, he was appointed Tongjisa and replaced Li Shunchen. However, he was far inferior to Li Shunchen in terms of navy, and was lazy in managing soldiers and fleets, however, on August 27, 1597 (July 15, 1597), Yuanjun was ambushed by the Japanese general Fujido Takaho at Checheon-leung, and Won-kyun, who took over the Korean navy, was under unfavorable command at the Battle of Checheon-leung, and the Korean naval division was almost completely destroyed, and Korea lost its sea control. Yuan Jun himself was killed in battle. The Japanese occupied several Korean islands, including Busan.
Upon hearing of Yuan Jun's crushing defeat, Emperor Xuanzu felt remorse for his hasty decision. In desperation, Emperor Xuanzu once again took up Li Shunchen, who had already been deposed. (Li Shunchen was murdered and imprisoned for rumors) When Li Shunchen arrived, only a few ships were left in the original painstakingly managed marine division. But because he was entrusted with the task of saving the country, he had to do his best in this adversity and set out to rebuild the navy at the Jeolla Provincial Water Camp. On August 28, Li Shunchen commanded this newly rebuilt marine division and once again fought a decisive battle against the Japanese marine division, and the decisive battle was in the Mingliang Strait. The Mingliang Strait is a narrow strait between Jindo and the mainland, with rapid currents. Due to the tides and waves, the direction of the current in the Mingliang Strait reverses every 3 hours. The strait is only about 294 meters wide and narrow enough to pull steel cables on both sides of the strait.
Li Shunchen was guarding the Mingliang Strait, but due to the weakness of his troops, he decided to set up traps and sent people to set up iron cables and wooden stakes on the shore when the tide was low. On September 16, japanese commander Takaho Fujido led more than 330 warships and 20,000 troops to attack the Mingliang Strait at high tide and completely annihilate the Korean naval division. In the early morning of October 26, when everything was ready, Li Shunchen first disguised civilian ships in the strait as warships to disturb the Japanese army and make them think that the Korean naval division had recovered. When the Japanese ships approached, Li Shunchen, who was hidden at the foot of the mountain, launched a fierce shelling of the Japanese ships. Since the Japanese ships were pointed-bottomed sea vessels, swaying in the turbulent currents, and Li Shunchen's navy was covered by mountains, he personally led 12 warships to lead the enemy deep into the Mingliang Strait. After successfully luring the Japanese into attack, they shelled the Japanese ships.
The Japanese wanted to launch a counterattack, but due to the geographical superiority of the Korean Navy, they could not launch a strong offensive. The Korean Navy seized the opportunity to launch an attack on the Japanese command ships, annihilating the Japanese command ships and 2 other warships, and killing the Japanese commander Raijima Tongzong on the spot. At this moment, the tide began to recede, the Japanese ships collided with each other, the situation was chaotic, and a large number of Japanese ships were crowded in the narrow strait, becoming extremely passive targets. The North Korean ships took advantage of the situation to attack, and the Japanese ships lost their commanders, and the military was distracted, so they had to retreat eastward along the tide, but they encountered iron cables and wooden stakes buried in advance by Li Shunchen and could not retreat. The North Korean Navy launched a general offensive, with 13 warships successfully sunk 36 Japanese ships, destroyed 92 ships, and killed more than 8,000 Japanese troops, a great victory, while North Korea only killed 14 people, not a single South Korean ship was lost. Korea once again severely damaged the Japanese marine division, successfully cut off the Supply Line of the Yellow Sea controlled by the Japanese army since the Battle of Jishan, and regained control of the sea. This is the Battle of Mingliang, as General Li Shunchen wrote in his diary, which is purely a blessing from Heaven and can be called a miracle in the history of naval warfare.
Japanese and Korean historians have different controversies about this historical battle.