In December 617 (the 13th year of Daye), Xue Ju, a rich man in Jincheng County, led 1, troops to invade Weishui, attack Fufeng and compete with Li Yuan for Guanzhong. Tang gaozu ordered Li Shimin to be handsome and fought against Xue Ju, beheaded more than 1, people, defeated Xue Ju, and extended Tang's influence to Longyou area, further stabilizing the situation in Guanzhong. In the second year of June, tang gaozu named Li Shimin marshal for the west, continue to crusade against Xue Ju. In July, he fought with Xue Ju in Jingzhou, because Li Shimin was suffering from malaria at that time and was recuperating in the army, so he was eager to fight a decisive battle. Due to insufficient preparation for the war, he was attacked by Xue Ju and was defeated. In August, after Xue Ju's death, his son Xue Rengao led the troops to invade. Li Shimin continued to go to war. He stuck to it for 6 days, forbidding his men to fight, and ordered: "Those who dare to speak and fight will be beheaded!" This is mainly to restore the morale of our own army, but also to demoralize the enemy. When the time was right, Li Shimin ordered his subordinates to lure the enemy in first, and then the whole army was dispatched to annihilate. The battle of Shallow Water Yuan greatly defeated the enemy. As a result, Xue Rengao surrendered and Longyou area was pacified.
in March 619 (the second year of Wude), Liu Wuzhou, with the support of the Turks, went south on a large scale and attacked Bingzhou, which is the Taiyuan area. Li Yuanji, the general manager of Bing, couldn't support it and fled back to Chang 'an. As a result, Jinzhou and other places also fell, and the Guanzhong area shook. Tang gaozu wanted to give up this area of Hedong, which was opposed by Li Shimin and others. He thought that Hedong was a land of wealth, an important support of Beijing, and a place to fight, so he couldn't give up, and he was willing to lead the troops back. Tang gaozu ordered Li Shimin to lead the troops to war. In November, Li Shimin took advantage of the freezing of the Yellow River to cross the river smoothly, and then confronted Song Jingang, the general of Liu Wuzhou, with the tactics of "keeping a firm wall down". Li Shimin couldn't hold out, frustrated the enemy's momentum, and stood by, because he knew that the enemy was going deep, and the food and grass would be exhausted. In February of the following year, when the Song Jingang army was short of food and grass, it defeated the enemy in Jiexiu City, and Liu Wuzhou also gave up Taiyuan and fled north. At this point, the northeast of Guanzhong has also declared stability.
In May of p>618 (the 14th year of Daye), after the news of Emperor Yangdi's murder reached Luoyang, the Shoujiang proclaimed Yang Dong, the King of Yue, as emperor and changed to Emperor Tai. In April 619 (the second year of Wude), Wang Shichong seized power, changed the country name to Zheng, and divided kanto region. In July of the following year, Li Shimin marched into Luoyang and began to pacify Wang Shichong.
from August of this year, the siege of Luoyang was completed, and in February of the following year, although the siege was often carried out day and night, it was impossible to win because Luoyang was strong. The soldiers were anxious to return home, but Li Shimin was firm in his will and encouraged them to say, "This time we came with heavy troops, and we should do it once and for all. The eastern States have already surrendered to the wind, leaving only an isolated city in Luoyang. Judging from the current situation, it is difficult to hold on for long, and the success will soon be achieved. Why do you give up and return in vain?" At Li Shimin's insistence, people said they would fight with him to the end.
In this decisive battle, Li Shimin always took the lead. On one occasion, he took 5 cavalry to patrol the terrain ahead, and was surrounded by enemy cavalry. Dan Xiongxin, the enemy general, took Li Shimin straight, and Wei Chijingde leaped out, stabbing Dan Xiongxin off his horse and covering Li Shimin's tight encirclement.
after that, it was the famous tiger prison battle.
At the critical moment when Wang Shichong was besieged and defeated, Dou Jiande of Hebei led hundreds of thousands of troops, claiming to be 3,, and went south in a big way to save Wang Shichong. At that time, Dou Jiande claimed to be King Xia, occupying Hebei and Shandong. He didn't want to rescue him at first, so he sat and watched the dragon and tiger fight. Later, when I saw that Wang Shichong was about to be wiped out at a disadvantage, I followed the advice of Liu Bin, a subordinate, and sent troops to rescue him, so as to avoid being alone and doomed after Wang Shichong's demise.
at first, Dou Jiande wrote to Li Shimin, asking him to retreat to Tongguan and make peace. Li Shimin flatly refused and began to deploy how to deal with Dou Jiande.
Li Shimin's subordinates are divided into two factions. One faction, mainly Xue Shou, thinks that Wang Shichong is short of food and grass now, and it is hard to predict the victory or defeat of the war in case of aid. Should be in the siege of Luoyang at the same time, by the king of Qin Li Shimin personally led the elite cavalry to seize Hulao Pass. After the defeat of Dou Jiande, Wang Shichong was broken.
However, Qu Tutong and other generals objected. They thought that going to Hulao Pass would be between Scylla and Charybdis, and they should retreat to Xin 'an first, and then look for opportunities to fight.
Li Shimin finally said, "Wang Shichong has run out of grain and grass, and it is centrifugal inside and outside, so we should take advantage of the surplus, so we don't have to make an attack. Dou Jiande, on the other hand, is arrogant and lazy, so we must occupy the tiger prison and guard the dangerous places. If Dou Jiande wants to fight with me, it will definitely win the first world war. If they cringe, then Wang Shichong will be defeated within ten days. If we don't make a quick decision now and let Dou Jiande occupy the tiger prison, then the cities that have just surrendered can't be guarded, and it will be difficult for our army to win again. "
Li Shimin finally adopted Xue Shou's advice. He ordered Qu Tutong and Li Yuanji, King of Qi, to continue to besiege Luoyang, and himself led 3,5 elite cavalry to rush to the Tiger Prison. The famous Tiger Prison War in history officially began.
In March of p>62 (the third year of Wude), Li Shimin led the troops to Hulao Pass. He personally went 2 miles eastward to spy on the enemy. Dou Jiande could not March, so he had to build a base on the spot and stick to it. In April, Dou Jiande's army lost several battles, and the soldiers' homesickness became more and more serious, and the morale of the army began to fall apart, and the grain transportation road was raided again, and the general Zhang Qing was also captured. At this time, the subordinates suggested that crossing the river to attack Huaizhou, then crossing Taihang Mountain to the west, taking advantage of the imaginary to capture Shangdang, and then going south to occupy the vast area of Hedong, which could not only occupy the territory to replenish troops, but also threaten Guanzhong, thus forcing Li Shimin to withdraw and save himself, and the siege of Luoyang was broken. But Dou Jiande was bent on finding a decisive battle with Li Shimin, and he simply wouldn't listen. Instead, he said it was a scholar's opinion.
On May 1st, Li Shimin crossed the river, herded horses on the north bank of the Yellow River, leaving thousands of war horses, giving Dou Jiande the illusion that he had run out of food and grass, and he himself returned to Tiger Prison at night.