Dou Jiande gathered a large army to attack westward in November of the third year of Wude, however, at that time, Dou Jiande's goal was not the Tang army and the Zheng army that were fighting desperately in the Central Plains, but only a righteous army active on the south bank of the Yellow River, led by a leader named Meng Haigong, with more than 30,000 people, Dou Jiande defeated him lightly, and then, one of his advisers continued to wave his army to the west, and actively participated in the Tang and Zheng wars that were fiercely fighting at this time. Defeating the two powerful opponents of Tang and Zheng in one fell swoop, so as to clear the obstacles to the unification of the world for King Xia, retreat, can also protect Wang Shichong's Zheng State, so as to maintain the three-legged momentum of the north.

This is a long-term plan for future generations, Dou Jiande naturally readily agreed, and Wang Shichong's messenger for help happened to arrive at this time, so Dou Jiande did not stop to rest his army, but continued to wave his army westward, towards the Luoyang battlefield at this time.

As soon as Dou Jiande's Xia Jun made a move, the Tang Dynasty spies had already discovered the news, so with the full operation of these spies, this information was quickly placed in front of the tables of Li Shimin, the King of Qin, and Li Yuan, the Tang Emperor, and was read by the two.

Tang Emperor Li Yuan was naturally shocked when he saw it, so he immediately convened the important ministers in the court to discuss countermeasures, and after the ministers put forward a lot of suggestions, Li Yuan decided to issue an edict to Li Shimin, who was in the army, ordering him to preserve his strength, and if Dou Jiande really led the army to attack, he would immediately withdraw the army to avoid fighting with the Xia army whose morale was flourishing.

Tang Emperor Li Yuan's messenger immediately set off from Chang'an, and then rushed to the army day and night, but it was not until he arrived in the army that the messenger was surprised to find that the generals in the entire military camp did not know the news that Dou Jiande had sent troops! The reason for this. It was Li Shimin, the king of Qin, who blocked the news.

The arrival of the envoy finally made the paper unable to hold the fire, and the news that Dou Jiande's Xia army was about to enter the war was like a drop of water dripping into a boiling oil pot, which suddenly stirred up a thousand waves. After all, after more than half a year of bloody fighting, the soldiers of the Tang Army were all exhausted. If the opponent was Wang Shichong's army, who was as tired as them, then they could continue to hold on, but when a new morale-boosting enemy appeared in front of the soldiers of the Tang army, the Tang army's will to fight inevitably weakened and became demoralized.

Li Shimin did not obey his father's order to withdraw from the army, he resisted pressure from above and below at the same time, and replied to his father. This time, he was sure of victory, and then, he issued a new military order: those who dare to speak will be killed! With his invincible record on the battlefield in the past, Li Shimin finally succeeded in suppressing the opposition of the whole army, and persuaded his father to agree to face Wang Shichong and Dou Jiande on both sides in Luoyang, and then look for opportunities in the war. Defeat these two enemies in one fell swoop and remove the obstacles to the unification of the world.

February of the fourth year of Wude. When Li Shimin finally won the decisive battle against Wang Shichong, Dou Jiande's army had also marched not far from Luoyang, and although Wang Shichong was defeated, he still led the remnants of his troops to occupy the city of Luoyang. Under these circumstances, Li Shimin made a decision, he ordered all the troops to go into battle except for the necessary troops to prevent Wang Shichong's surprise attack on the city, and first dug a deep trench on the periphery of Luoyang Jiancheng. Then, relying on the trench, to build the fortifications used to prevent the enemy from breaking through, under the full supervision of Li Shimin, in just one month, the originally leveled land around Luoyang City has become a large area of huge defensive situation project, and when this project is finally completed, Li Shimin, also finally relieved, surrounded by such a solid defense system, Wang Shichong even if he still retains an elite army in his hands, but after all, he can not break through this line of defense, so, When he led the army to face Dou Jiande, Wang Shichong's army would not be able to play any role, and the only thing he could do was to sit in the lonely city, and then sit and watch the two families divide the victory.

In March of the fourth year of Wude, the Tang army under the strong order of Li Shimin, finally built a comprehensive blockade of Luoyang Wang Shichong's fortifications, and at this time, according to the news from the Tang army scouts, Dou Jiande's Xia army, from the gateway of Henan Tiger Prison Pass has been less than 100 miles, at this time due to the fortifications just built with all their might, the Tang army is exhausted, so Li Shimin handed over the army to Li Yuanji, the third brother of Qi who has been learning from himself to lead the army to fight during this time, but he led only 3,500 Xuanjia cavalry, each with two war horsesAfter a day and a night of desperate raids, Li Shimin and his Xuanjia cavalry finally arrived at the Tiger Prison Pass before the arrival of the Xia army.

There were already thousands of men and horses stationed on the Tiger Prison Pass, and after Li Shimin led the Xuanjia cavalry to arrive, the total strength of the Tang Army on the Tiger Prison Pass was close to 10,000, which of course was far from being comparable with the number of tens of thousands of Dou Jian's German army, however, relying on the dangerous terrain of the Tiger Prison Pass, it was enough to withstand the strong onslaught of Dou Jiande's army, and these thousands of Xuanjia cavalry were all the elite of the army, each of which was enough to be one as ten, so the military heart of the original army was stabilized. And Li Shimin personally inspected the defense, and then he rested with peace of mind.

A few days later, the Xia army also went to the Tiger Pass, Dou Jiande tried to launch several attacks, but they were easily repelled by Li Shimin by taking advantage of the geographical advantage, Dou Jiande clearly knew that with such a dangerous terrain as the Tiger Pass, too many troops could not be deployed at all, so it was impossible to give full play to the numerical advantage of the Xia army, even if it was a strong attack, it may not be able to capture this Xiongguan, but to lose a large number of troops, and once too many troops were lost, even if they could capture this dangerous Xiongguan, it was more than worth the loss. Therefore, for a while, Dou Jiande's heart fell into a dilemma.

At this time, Wang Shichong, who was still holding on to Luoyang City, would not have thought that when he was waiting for Dou Jiande to lead the army to rescue him, even Dou Jiande himself fell into deep distress because of his indecisiveness. (To be continued......)