Since July of the fourth year of Wude, Liu Heimin has raised troops against the Tang Dynasty. He borrowed a large number of cavalry from Jieli Khan to the north, and united with Xu Yuanlang to the south, and the army became stronger and stronger.

In just five months, Liu Heimin defeated Li Shentong and Li Yi sent by Li Yuan in a row, and successively captured Jizhou, Zhaozhou, Xiangzhou, Lizhou, Weizhou, Xingzhou, Zhaozhou, and Xinzhou, and completely recovered Dou Jiande's hometown, and the troops were even more fierce than it.

Seeing this situation, Li Yuan had no choice but to order Li Shimin, the king of Qin, and Li Yuanji, the king of Qi, to command 80,000 troops to conquer Liu Heimin.

After the Battle of Wujiaoguan, Li Shimin's soldiers were already quite old.

Moreover, Datang has already made a preliminary decision on the world, and the resources and troops that can be mobilized are far beyond Liu Heimin's ability.

In this battle in Hebei, Li Shimin put his strategic focus on Liu Heimin's base camp - Zhaozhou City, and he wanted to go straight to Huanglong Mansion.

Li Shimin first made a feint attack from the western part of Hebei to attract Liu Heimin's main force to attack, but when Liu Heimin arrived with his troops, he played a game of cat and mouse.

After that, he ordered Li Yi, the governor of Youzhou, to attack Liu Heimin from the north, Li Yi fought desperately, Lian Keding, Luan, Lian, Zhao Sizhou, Liu Heimin was shocked when he heard the news, and hurriedly mobilized the army to the north to rescue.

Seeing that the plan to divert the tiger from the mountain had worked, Li Shimin immediately ordered the main force of the Tang army to attack the city of Zhaozhou on all fronts, and soon occupied the city.

Liu Heimin was fighting in the north, and when he heard that the nest had been destroyed, he led the main force back to Zhaozhou, and the two sides launched a fierce battle under the city of Zhaozhou.

The city of Zhaozhou was surrounded by water on all sides, and it was difficult for the infantry to attack the city, so Liu Heimin ordered the soldiers to build two roads in the northeast of the city, and recruited troops everywhere to besiege the city.

Li Shimin saw that there were more and more soldiers besieging the city of Liu Heimin, and he was worried that he would be trapped in the lonely city, so he led his troops to break through and transferred troops from all over the country to fight for the city of Zhaozhou.

A few days later, Liu Heimin's repaired Yongdao did the Tang army a great favor, and they took advantage of the convenience of Yongdao to directly attack the city.

Liu Heimin couldn't defeat him, so he had to lead his troops to flee in a huff.

Liu Heimin was unwilling to abandon the city of Zhaozhou, and he recruited troops and transported grain from all over the country, wanting to recapture the city again.

Li Shimin ordered his troops to cut off Liu Heimin's grain route and set fire to the ships, chariots and horses that were transporting a large number of people, causing Liu Heimin to fall into a predicament.

Li Shimin expected that Liu Heimin would soon come to a decisive battle, so he followed Han Xin's example and built a dam in the upper reaches of the river, causing the river to become shallow.

Liu Heimin made a bloody investment this time, he collected 20,000 cavalry at a time, and wanted to go to the city of Zhaozhou to fight Li Shimin to the death.

When the war horse swam across the water, Li Shimin ordered the general guarding the weir to break the embankment to prevent water.

The flood roared down, and the main force of Liu Heimin's cavalry was swept to the east by the monstrous flood, and almost all of them were fed to the fish and turtles.

When the flood dissipated, Li Shimin led his troops to clean up the mess, and wiped out the opponent almost without spending any troops.

Liu Heimin was helpless, and only fled north to the Turks with more than 100 personal soldiers.

Hebei was pacified again.

As for the garrison task, Li Yuan issued an edict to Li Shimin to hand it over to Li Yuanji, and he had a new appointment.