In 620 AD, the traitorous king Shichong of Luoyang, the eastern capital of the Central Plains, after defeating Li Mi of the Wagang Army, began to expand externally, and basically eliminated the power of the Tang Dynasty in the Central Plains within half a year. Tang Gaozu Li Yuan was furious that any emperor would allow others to do anything wrong on his own territory, so he sent Li Shimin, the king of Qin, who had just defeated Liu Wuzhou and Song Jingang in the Three Jin Dynasty, to lead an army to recruit Wang Shichong.

On the first day of July of the same year, Tang. Under the leadership of Li Shimin, the army went out to attack Wang Shichong. Wang Shichong had already anticipated that Tang would take Zheng as the next target when Liu Wuzhou and Song Jingang were annihilated, so he had already prepared for mobilization.

According to the military comparison of Tang and Zheng at that time, although Zheng was slightly weaker, he won the battle at home, and took a defensive position, and there should have been a more tragic tug-of-war scene, but as soon as the war began, Wang Shichong's situation deteriorated rapidly, and the defenders of Zheng State surrendered without a fight. In July, Zhang Gongjin descended; In August, Dengzhou fell; In September, Tian Zhan descended to 25 states in the department, and Shi Derui descended to 7 states in the department; In October, the general Zhang Zhen surrendered, Guo Qing surrendered to Guanzhou, Wei Lu surrendered to Xingyang, and Wang Yaohan surrendered to Bianzhou. In just three months, all the counties around Luoyang fell into the hands of Li Shimin, and Luoyang became an isolated city.

Wang Shichong was unexpected, shocked, and exclaimed in his heart: "How can this be? This Tang Dynasty's "God of War" Qin King Li Shimin really deserves his name, but ......

But that's too powerful, isn't it? ...... "I couldn't sleep all day and night, and I was terrified.

Seeing that the situation was unfavorable, Wang Shichong had to personally come out to Li Shimin to seek peace, and the two sides negotiated outside Luoyang City across Luoshui, but in the end the peace talks broke down. Li Shimin sent soldiers from all walks of life to attack Wang Shichong's town, and the momentum was like a bamboo, and he won in one fight.

In September, Wang Junkuo conquered Wang Shichong's Anyuan County, and went east to capture Guancheng before returning, so all the states and counties in the Central Plains surrendered to the Tang Dynasty.

At this time, Wang Shichong had lost his own fight against Tang. The ability of the army, as a last resort, had to send a messenger to Dou Jiande for help, Dou Jiande and Wang Shichong were friends and enemies, and the two sides often fought because of turf disputes in the past.

Wang Shichong's move was really to quench his thirst, but there was no other way. "The enemy of my enemy is my friend!" Now Dou Jiande is also the target of the Tang Dynasty to be eliminated, so after Dou Jiande received Wang Shichong's letter asking for help, after thinking twice, he knew the truth of "cold lips and cold teeth", and finally decided to turn enemies into friends with Wang Shichong and agreed to help Wang Shichong. Wang Shichong was overjoyed when he heard the news, and immediately sent his brother's son Wang Wan and Neishi Ling's eldest grandson An Shi to pay a return visit, asking Dou Jiande to send troops to help as soon as possible.

On this day, Li Shimin, the king of Qin, led Wei Chi Jingde to lead 500 Xuanjia elite cavalry to observe the enemy situation on a high ground near Luoyang City.

Li Shimin had no fear, pulled out his Tang sword, and led five hundred Xuanjia elite cavalry to rush into the enemy formation and kill the enemy bravely. Suddenly, Wang Shichong's "10,000 enemies" brave general Shan Xiongxin raised his lance and rode his horse, and took Li Shimin like lightning. Li Shimin was entangled by several enemy troops at this time, unable to separate, at the moment of crisis, Wei Chi Jingde roared, jumped forward, and stabbed Shan Xiongxin under the horse with a lance, saving Li Shimin's life. Li Shimin, Wei Chi Jingde and 500 Xuanjia soldiers rushed back and forth in the camp of 10,000 infantry of the Zheng army, as if entering a no-man's land, Wang Shichong, who was killed, was shocked. At this time, Qin Qiong led reinforcements to rescue, and Wang Shichong hurriedly ordered the Zheng army to withdraw into the city.

Afterwards, Li Shimin recalled that Xia Xue had said that Wei Chi Jingde would save his life, and this time it really came true. sighed in his heart, this beautiful little fairy is really not a mortal, and he couldn't stop thinking about Xia Xue in his heart, "Xue'er, if you were by my side now, how nice it would be!" ”

On the thirteenth, Li Shimin transferred the military camp to Qingcheng Palace, and before the barrier was repaired, Wang Shichong led 20,000 soldiers and horses out from Fang Zhumen, relying on the walls and ditches of the old horse square, close to the valley to resist the Tang. The generals of the army and Tang were all panicked. Li Shimin let the elite cavalry line up in the Beibi Mountain, and he climbed the tomb of Emperor Xuanwu of the Northern Wei Dynasty to observe the Zheng army, and said to the people around him: "The situation of the thief is already embarrassing, and he wants to get away with it, and he wants to get away with it, defeat him today, and he will never dare to fight again in the future!" ”

Li Shimin ordered Qu Tutong to lead 5,000 infantry across the valley to attack Wang Shichong, and warned Qu Tu Channel: "As soon as the army fights, fireworks will be set off immediately. When the smoke rose, Li Shimin led five hundred Xuanjia cavalry to attack the south, taking the lead, and fighting hard with Qu Tutong's combined forces. Li Shimin wanted to know the distribution of the forces of Wang Shichong's army formation, so he led dozens of elite cavalry to rush into the enemy formation, and rushed all the way to the back of the enemy formation, which was unstoppable and killed and wounded many enemies. Soon, due to the limitation of the causeway, Li Shimin and the cavalry were separated, only the general Chi Jingde followed Li Shimin, and several Wang Shichong's cavalry caught up, and Li Shimin's mount was killed by an arrow. Wei Chi Jingde turned his horse's head and rode back, shooting at the chasing Zheng soldiers, the arrows were not missed, and the pursuers did not dare to move forward. So Wei Chi Jingde dismounted and gave his mount to Li Shimin, he walked in front of the horse to open the way, holding a long knife to jump and roar, extremely powerful, a row to kill more than a dozen enemy soldiers, Li Shimin also bent the bow and shot arrows on the horse, the arrows were not missing, shot many Zheng soldiers, the frightened Zheng soldiers avoided one after another, the two cooperated tacitly, and finally killed a bloody road, rushed out of Wang Shichong's army array, and was able to return to Tang. Military troops. Wei Chi Jingde saved Li Shimin again.

The dying and struggling Wang Shichong also led his subordinates to fight to the death, and the army dui was scattered several times and then reassembled, fighting from early morning to noon, only to kill the sky and the earth, the sun and the moon were dark, and Wang Shichong's army dui was finally defeated by Li Shimin's Tang. The army had to retreat in a hurry.

Li Shimin waved his army in pursuit until he reached the city, where he captured and annihilated 7,000 people. Tang hussar general Duan Zhixuan struggled to engage Wang Shichong's soldiers, deep into the enemy formation, the mount fell, Duan Zhixuan was captured by Wang Shichong's soldiers, two cavalrymen clamped him and grabbed his bun, ready to cross the river, Duan Zhixuan jumped bravely, the two cavalrymen were taken off their horses, Duan Zhixuan rode on his horse and ran back to Tang. Army, there were several hundred cavalry chasing behind, but did not dare to approach. Wang Shichong saw that Li Shimin's subordinates were all brave soldiers, and he couldn't help but sigh.

In February 621 AD, Wang Shichong sent the general Wang Kang to lead more than 10,000 Zheng troops out of the city to meet the enemy, and the Qin king Li Shimin's army dui confrontation, however, as soon as the battle, Li Shimin's elite Xuanjia cavalry killed the Zheng army on their backs, Wang Shichong's army dui had to be defeated, Li Shimin led the Tang . The army pursued the victory. and sent a thousand Xuanjia cavalry to go around behind Zheng Jun and stop outside the Luoyang City Gate to block and kill.

Wang Shichong's infantry could not enter the city, and fled south in panic, and Li Shimin's army pursued and killed several thousand men and captured more than 5,000 people. Wang Shichong was so frightened by Li Shimin's killing that he didn't dare to go out of the city again, but just surrounded the city and waited for Dou Jiande's rescue.

When Li Shimin, the king of Qin, attacked Wang Shichong in Luoyang, Dou Jiande received a letter from Wang Shichong asking for help.

Liu Bin, Dou Jiande's Zhongshu She, analyzed him and said: "Now the Tang State occupies Guanzhong, the Zheng State occupies the Central Plains, and we occupy the land of Yan and Zhao. Hearing that Tang used all his forces to attack Wang Shichong, for two consecutive years, Zheng's situation became more and more urgent day by day, and Tang's siege did not relax. Tang's troops are strong, Zheng's troops are weak, and the development trend is inevitably to defeat Wang Shichong, and Wang Shichong is defeated, so we have worries about death. For your sake, it's better to rescue Wang Shichong, Wang Shichong is resisting inside, and we are attacking outside to defeat Tang. The army is certain. If you beat away Don. The army has preserved Wang Shichong, which is a strategy to maintain a three-point situation for a long time. If Don. After the army is defeated, Wang Shichong can also be defeated, so take the opportunity to destroy him, concentrate our forces and Wang Shichong's forces, and take advantage of the Tang Dynasty. When the army is defeated, it will be able to fight directly to the west, and Chang'an will be able to get it, which is the basis for pacifying the world. ”

Dou Jiande was very happy after hearing this: "Wonderful! Wonderful! That's a good strategy! ”

So Dou Jiande sent his servant Wei to Chang'an to meet Tang Gaozu and ask for the lifting of the siege of Wang Shichong. Tang Gaozu Li Yuan flatly refused.

In February 621, Dou Jiande, who was furious, personally led a large army to attack Zhouqiao City of Tang State, conquered Zhouqiao City in less than three days, captured Meng Haigong, and left the general Fan Yuan to guard Caozhou, leading Meng Haigong and Xu Yuanlang to rescue Wang Shichong.

Along the way, they successively conquered Yuanzhou, Liangzhou, and Guanzhou of the Tang Kingdom, and the momentum was like a bamboo, and the attack was overwhelming, and finally the army gathered in Xingyang.

Hearing the news that Dou Jiande led a large army to rescue Wang Shichong in Luoyang, Li Shimin convened the generals to discuss the matter, and everyone asked to avoid Dou Jiande's soldiers, and the eldest grandson Wuji said: "Wang Shichong is at the end of the road, and he will soon become a prisoner, Dou Jiande came from afar to rescue Wang Shichong, which is the will of heaven to Zheng and Xia to perish." We should rely on the danger of the tiger prison to resist Dou Jiande, depending on the situation, we will definitely be able to defeat them! ”

Fang Xuanling said: "Wang Shichong is based in the eastern capital, the warehouses are full, and the soldiers and horses under command are all the elite of the Jianghuai region, and the current difficulty is only a lack of food. Because of this, we were dragged back, and we couldn't fight if we wanted to, and it was difficult to hold on for a long time. Dou Jiande personally commanded the army to come to the aid from afar, and he would also do his best. If he is allowed to come here, the two Kou join forces and transport the grain from the land of Yanzhao to supply Luoyang, then the war will begin, and I don't know when it will end, and the day of unifying the world is even more distant. Now we should divide our forces to besiege Luoyang, deepen the trenches and increase the barriers, if Wang Shichong sends troops, be careful not to fight with him, King Qin, you personally lead the brave elite, occupy Chenggao first, sharpen the weapons and train the soldiers and horses, and wait for them to arrive, and wait for the rest of the work, and will definitely be able to defeat the enemy. After defeating Dou Jiande, Wang Shichong will naturally be defeated, and within twenty days, he will capture two monarchs! Li Shimin greatly appreciated his strategy.

Xiao Yu, Qu Tutong, Feng Deyi, Hou Junji, and Li Junxian all believed: "Our army is exhausted and demoralized, Wang Shichong is not easy to conquer quickly by virtue of the strong city, Dou Jiande came with the momentum of victory, morale is high and unstoppable, our army is attacked by the enemy, it is not a good way, it is better to retreat and guard Xin'an, so as to wait for the opportunity." ”

Li Shimin said with a firm gaze: "Wang Shichong has lost his troops, the grain has been eaten, and he is centrifuged up and down, we don't have to spend energy to attack, we can sit back and wait for him to be defeated." Dou Jiande has just defeated Meng Haigong, and he has won one victory after another along the way, the generals are proud, the soldiers are tired, and we occupy the Tiger Prison Pass, which is equivalent to choking his throat. If he ventures a decisive battle, we can easily defeat him; If he hesitates and does not come to the battle, in less than ten days and half a month, Wang Shichong himself will be defeated. After the city was broken, the strength of the army increased, and the morale of the army naturally doubled, and the defeat of two enemies at once was in this battle. If he does not march quickly, Dou Jiande will enter the Tiger Prison Pass, and the surrounding cities will be newly annexed, and he will definitely not be able to hold on; When the two enemies join forces, the forces will inevitably be strong, how can there be an opportunity? I've made up my mind, let's stop arguing! ”

Qu Tutong, Hou Junji, Li Junxian and others asked to lift the siege of Luoyang, but Li Shimin did not agree to see the changes in the enemy by virtue of the danger. Li Shimin, who had made up his mind, decisively ordered the general Dui to divide into two parts, with the eldest grandson Wuji, Qu Tutong and others leading 1,500 Xuanjia elite cavalry and 20,000 infantry to continue to besiege the eastern capital Luoyang, and Li Shimin led 3,500 Xuanjia elite cavalry to the east to go to the Tiger Prison Pass. Li Shimin set off at noon, crossed Beipi, went to Heyang, and went by way of Gongxian. Wang Shichong boarded Luoyang City to see Tang. Army action, I don't know Don. The army did not dare to go out of the city to fight.