In May, Shen Yue, Wang Shichong's Zhengzhou (Zhihu Prison Pass) division, sent people to Li Shiji, the general of the Tang marching army and the general of Zuowuhou, to ask for surrender.

Since Li Shiji was sent by Li Yin to capture Guanzhou, his main task is to capture the Tiger Prison Pass, but the Tiger Prison Pass is easy to defend and difficult to attack, and it is difficult to ascend to the sky if he wants to attack strongly, and Shen Yue's invitation to surrender made Li Shiji see the hope.

At night, Li Shiji led his troops to attack the Tiger Prison, and Shen Yue responded internally, seized the Tiger Prison Pass in one fell swoop, and captured Wang Xingben, the king of Jing of Zheng State, and his elder Shi Dai Guan.

On 15 May, Li Shimin sent the hussar general Duan Zhixuan and the governor of Tangzhou, Wang Junkuo, to lead 20,000 troops to attack the Mengjin Bridge.

There were 8,000 people in the Mengjin crossing army, and after receiving the message for help, they sent 5,000 troops to the Mengjin Bridge, but when they were halfway through the march, they suddenly saw the Mengjin ferry burning into the sky from a distance, and they were immediately shocked and hurriedly turned back.

However, when the Mengjin Crossing Water Army returned to the ferry, they suddenly found that the flag on the gate of the Water Village had become that of the Tang Army.

Li Shimin sent troops and horses to attack Mengjin Bridge from the land, while Li Yin sent Zhang Yasha, the captain of the naval academy, to wait for his main force to leave Mengjindu, and quickly attacked and captured Mengjindu.

Since many of the families of the navy were in the water village, the 5,000 soldiers rowed to the water village to surrender despite the generals' obstruction.

And because there was no support from the Mengjin Ferry Naval Army, Mengjin Bridge fell after two days of fierce attack by Duan Zhixuan and Wang Junkuo's army.

So far, Luoyang eight strategic places, has been captured for the Tang Dynasty six of them, only the southeast of the Xuan Pass and the south of the Que Sai Pass are still in the hands of Wang Shichong, and because the location of the Xuan Pass and the Que Sai Pass is not in the Tang Army's main force to enter Luoyang route, so at this time to encircle Luoyang, the time is also ripe.

Li Shimin then wrote a memo with Li Yin, sending Yu Wenshi and Chang'an to request an army to besiege the eastern capital Luoyang.

Li Yuan said to Yu Wenshi: "Go back and tell the King of Jin and the King of Qin, this time to attack Luoyang, do not win a complete victory, never withdraw troops, when the capture of the Eastern Capital, the Sui Dynasty royal family's chariots and honor guards, books and equipment, except for what everyone needs, will be entrusted to you to collect, and other men and women jade cloth and silk are used to distribute to the soldiers." ”

On May 23, 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 Fangzhumen, relying on the walls and ditches of the old horse workshop, close to the water to resist the Tang army, and the Tang generals were all panicked.

Li Shimin let the elite cavalry line up in the Beibi Mountain, climbed the high ground to observe the Zheng army, and said to the people around him: "The thief's situation 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 Tutong: "As soon as the army encounters, fireworks will be set off immediately." ”

When the smoke rose, Li Shimin led the cavalry to the south, took the lead, and joined forces with Qu Tutong to fight hard. 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 scattered, only Qin Shubao followed Li Shimin closely, several Wang Shichong's cavalry caught up, Li Shimin's mount was killed by an arrow, Qin Shubao turned his horse's head to ride back, and shot the chasing Zheng soldiers, the arrows were not missing, and the pursuers did not dare to move forward.

So Qin Shubao dismounted and gave his mount to Li Shimin, walked in front of the horse, jumped with a long knife in his hand and shouted to kill a few people, rushed out of Wang Shichong's army formation, and was able to return to the Tang army.

Wang Shichong also led his subordinates to fight to the death, and the army was scattered several times and then regrouped, and Wang Shichong's army did not retreat from morning until noon.

In the final engagement, Duan Zhixuan struggled to engage Wang Shichong's soldiers, went deep into the enemy formation, the mount fell, Duan Zhixuan was captured by Wang Shichong's soldiers, two cavalrymen clamped him and grabbed his hair bun, ready to cross the river, Duan Zhixuan jumped bravely, the two cavalry fell off their horses, Duan Zhixuan rode on his horse and rushed back to the Tang army, there were hundreds of cavalry chasing behind, but did not dare to approach.

Li Shimin then ordered the army to march towards Luoyang, and the servants of the line shot Qu Tutong, and Dou Liang, the prince of Zanhuang, led the troops to patrol the camp, and suddenly encountered Wang Shichong, lost the battle, and retreated.

Seeing that the army of Qu Tutong and Dou Liang was about to be defeated, Li Shimin led his 3,000 Xuanjia army to rescue, Wang Shichong was defeated, and the Tang army captured Wang Shichong's cavalry general Ge Yanzhang, captured and annihilated more than 6,000 enemies, Wang Shichong fled back to Luoyang City with only a few hundred people, and the plan to obstruct the Tang army's march to Luoyang failed again.

Every time he fought, Li Shimin personally put on black armor and led the Xuanjia Army as the vanguard, taking the opportunity to attack, invincible, and making the enemy fearful.

After repelling Wang Shichong's soldiers and horses, Li Shimin continued to lead the army to march to Luoyang, and finally surrounded Luoyang Palace, Wang Shichong's defense in the city was very tight, the cannon could shoot fifty pounds of stones, throw two hundred steps away, there were eight bows of crossbows, the shaft of the arrow was like a spoke, and the arrow was like an axe, which could shoot five hundred steps away.

Li Shimin attacked the city from all sides, day and night, and failed to conquer it for more than ten days. There were dozens of people in the city who wanted to use the city to defect to the Tang army, but they were killed by Wang Shichong before they could be launched. Since Wang Shichong arrived in Luoyang, no one has been able to launch a conspiracy under his nose.

After a long period of hard fighting, the Tang army soldiers were exhausted and wanted to return to Guanzhong, the chief manager Liu Hongji and others asked the class to return to the court, Li Shimin said: "Now that we are coming in a big way, we should do it once and for all." The states east of Luoyang have been subdued, only Luoyang is a lonely city, its momentum can no longer last, success is imminent, how can you give up and return to the dynasty? ”

So he ordered the whole army: "Luoyang will not be broken, and will never return to the army, and anyone who dares to mention the class teacher will be beheaded." ”

Everyone didn't dare to mention the class teacher again. After Gaozu heard about it, he also sent a secret edict to Li Shimin to return to the army, Li Shimin explained that Luoyang must be conquered, and sent a staff officer to return to the court to face the situation in front of Chen's army.

Feng Deyi said to Li Yuan: "Although Wang Shichong has obtained many places, they are only subordinates with a slight connection, and the actual order can only govern Luoyang City, he has exhausted his wisdom, and the day of Kecheng is in the near future." Now if he returns to the division, his power will be reinvigorated, and with the alliance of various places, it will be difficult to destroy him in the future! ”

So Li Yuan followed Li Shimin's advice. Li Shimin wrote to Wang Shichong, knowing that he would be harmful, but Wang Dangshichong did not reply.