It has been seven days since the Northern Sui Dynasty captured Wuyuan County. Zhang Xuan has been inspecting Wuyuan County and Yulin County these days, and is also waiting for news from Chang'an.

That morning, ten miles east of Yulin County, a cavalry of more than 100 people rushed to the east. Soldiers had already rushed to report to Zhang Xuan. When Zhang Xuan arrived at the city gate, the cavalry had already entered the city. Zhang Xuan immediately saw a familiar figure, and military advisor Fang Xuanling actually arrived.

Zhang Xuan smiled and went up to meet him, "Why is the military advisor here?"

Fang Xuanling turned over and got off the horse and smiled, "Of course I came to report the situation in Loufan County to Your Highness, and I realized that Hetao was so close!"

Everyone laughed, the cavalry saluted to them together, Zhang Xuan comforted them a few words, and then he came to the county yard with Fang Xuanling. Of course, Zhang Xuan knew that Fang Xuanling had something important to come.

The two sat down in the lobby of the county government, and a entourage served them tea. Zhang Xuan took a sip of tea and asked, "What's the situation in Chang'an?"

"I came for the matter of Chang'an, and the situation was not very good."

Fang Xuanling took out a tube of eagle letter and handed it to Zhang Xuan. Zhang Xuan shook out the content from the tube, which was a roll of fine silk wrapped in a small note.

Fang Xuanling explained: "The small note was written by Ling Zongjun, and it should have been written in a hurry. The thin silk is an explanation from the Intelligence Bureau. Mr. Wen, Ling Zongjun and others have been under house arrest by Li Yuan. This note was obtained by a Yu Yun's general guard from Ling Zongjun on the road and transferred it to Gao Jin in time."

Zhang Xuan opened the small note and took a look. Although it was only a short sentence, the content was very rich. Not only did the Hetao negotiations break down, but Li Yuan also refused to fulfill the agreement reached before and did not hand over to the North Sui Dynasty to Changsha and other five counties, which made Zhang Xuan furious.

Zhang Xuan is not surprised that the Hetao negotiations have broken down. It is inevitable that the breakdown will be achieved. Li Yuan cannot tolerate the Sui army's expansion westward and will definitely ask the Sui army to withdraw from Hetao. But how could the Northern Sui agree? It is normal for the two sides to have a sharp conflict over this, but Zhang Xuan cannot tolerate Li Yuan tearing up the last agreement.

Zhang Xuan Senran said: "It seems that he will not cry until he sees the coffin!"

"It's just for this matter that I am here."

"What good advice does the military advisor have?" Zhang Xuan asked with restrained the anger in his heart.

"I think this matter is easy to solve. As long as your Highness issues a manifesto to attack Song Jingang, I believe Li Yuan will have to give in. As the saying goes, the army will be attacked without sending one soldier to solve this storm. Why not do it?"

Zhang Xuan did not answer immediately. He paced back and forth in the room with his hands behind his back. At this time, Zhang Xuan had calmed down and he needed to think about this matter carefully.

The fundamental reason why Zhang Xuan asked the Northern Sui envoy to serve the Tang Dynasty was for Hetao. He wanted to set up a trap to allow the Sui and Tang Dynasties to reach an agreement. The Northern Sui attacked the Liang Shidu and the Tang Dynasty attacked Song Jingang. He also secretly supported Song Jingang, consuming the national strength of the Tang Dynasty to the greatest extent, making the Tang Dynasty unable to attack Lingwu County and even Hetao.

When the Northern Sui completely gained a foothold in Hetao, he would attack Song Jingang again and occupy Yan'an County in one fell swoop. At that time, Chang'an would also be under the army of the Northern Sui Dynasty.

Now Li Yuan seemed to see through his intentions and refused to give in to Hetao. He even used Xiao Xian's territory to threaten. If it were just a threat, Li Yuan would never feel pain.

Thinking of this, Zhang Xuan said slowly: "No need to issue any manifesto. We will send troops to Diaoyin County to capture their iron ore, and at the same time break their attack on Song Jingang. Since Li Yuan tore up the agreement, it is normal for the two armies to fight in Diaoyin County."

Seeing that Zhang Xuan had made up his mind, Fang Xuanling stopped persuading him and said, "Your Highness can only use troops, and I will ensure the logistics supply!"

Diaoyin County is located in the south of Yulin County, which is today in Suide and Mizhi areas in Shaanxi. The Sheyan River flows from the west, forming two parts of Diaoyin County. The densely populated areas in the south have been occupied by Song Jingang, but the northern part, which has a sparse population and a relatively harsh environment, is still controlled by the three thousand Tang troops.

The reason why the Tang army attached great importance to the northern part of Diaoyin County was that the largest iron ore in the Tang Dynasty: Hetiot Mountain, at the junction of the northern part of Diaoyin County and Shuofang County, had 3,000 Tang troops specifically guarding this iron ore and a smelting ground. In the future, the Tang Dynasty would obtain 30 million kilograms of pig iron and millions of kilograms of thick copper from here every year. A large amount of pig iron and thick copper were carried by hundreds of small boats, entering the Yellow River along the Sheyan River, and then heading south from the Yellow River to Guanzhong. This is much more convenient than transporting it from Jiangxia to Guanzhong.

However, Sheyanshui has been controlled by Song Jingang's army, so the transportation of pig iron and crude copper was suspended at the beginning of the year, and the mine warehouses have accumulated a large amount of pig iron and copper ingots.

The reason why Song Jingang's army did not come to rob these pig iron and thick copper was that the Tang Dynasty deployed a Tang army of more than 10,000 people in Shuofang County, close to Diaoyin County, which made Song Jingang's army quite afraid. Once they crossed the Sheyan River to the north, the Tang army of Shuofang County would immediately kill them and cut off their retreat.

In addition, Song Jingang is not short of pig iron and copper for the time being. He is not very interested in attacking mines. At present, Song Jingang's biggest test is how to defeat the attacks between the north and south of Li Gaoqian, the general of the left guard of Shangjun and Duan Decao, the general of the Tang army of Shuofang County.

Heti Mountain is located near Rulin County about 80 miles north of the Sheyan River. Not far from the county town. Heti Mountain was originally called Rust Mountain. Because the mountain has no trees, the whole mountain looks like it has rust, so it is called Rust Mountain.

When officials from the Ministry of Works of the Tang Dynasty discovered that this mountain of more than a hundred miles long was a very high-quality iron ore last year, they changed the name of Rut Mountain to Heti Mountain and set up a mining supervisor in Rulin County, recruiting 30,000 miners from several nearby counties to mine iron and smelting, and 3,000 troops were stationed here at the same time.

The mining of mines has gradually flourished Rulin County not far away. Many miners' families have moved here. Coupled with the consumption of miners, the business in Rulin County has developed rapidly. There are many wine shops, brothels, gambling halls, inns, medicine shops, music shops, mule and horse shops, shops, etc., and there are more than a dozen wine shops and brothels alone. In just one year, the population of Rulin County has grown from the initial thousands to tens of thousands.

More than 7 million kilograms of pig iron and two million kilograms of thick copper that had not been transported out were piled up in the warehouse in Rulin County. Li Yuan was also very anxious about this. He hoped to defeat the Song Jingang army of Diaoyin County as soon as possible and transport the pig iron and thick copper back to Chang'an.

To this end, after Li Yuan's second son Li Shimin sent troops to the county, he made another decision, urgently transferred Duan Decao, the general who was besieging Liang Shidu, to Yanlu County, Shuofang County, where to launch a north attack on Song Jingang.

But before the two-sided offensives of the Tang army began, a 20,000-strong Northern Sui army, led by Zhang Xuan, killed from Yulin County and rushed towards Chitie Mountain.

The general who guarded the mines in the Tang army was named Xi Shiling. It turned out that a thief commander from Hongnong County. When Li Yuan raised his troops to Tongguan, he led his troops to surrender to Li Yuan and was named General Zhendong and Duke of Yan County.

However, Xi Shiling was just a rioter with limited ability. After Li Yuan established the Tang Dynasty, he gradually stopped being valued. Currently, he is the general of Chai Shao, the general of Zuo Yigu, and was sent to Diaoyin County to guard the iron mine last year.

Xi Shiling was sent to Diaoyin County, which had a relatively harsh environment, to serve as the commander of Diaoyin County, which was actually a disguised dethronement. Li Yuan originally promised that he would be the commander of Hongnong County, but now he is just a guardian of an iron ore, which made Xi Shiling extremely depressed.

In the morning, a mail tower on the top of the Heti Mountain suddenly sounded a rapid alarm bell, "Dang! Dang! Dang! Dang!" This was an alarm that an enemy was attacking. At this time, three thousand Tang soldiers happened to come out of the military camp. They were going to various mines to supervise the work of miners. They lost them what was originally a supervisor.

The sudden alarm sound made all the Tang soldiers look at each other. Xi Shiling suddenly realized that it must be Song Jingang's army coming. Such a rushing alarm sounded that at least tens of thousands of troops were coming. His top priority was not to protect the mine. The mine bandit army could not move away, but to protect the warehouse in the county town, where there were a large amount of pig iron and copper ingots, and there was also one of his concubines in the county town. Once the thief army entered the city, the consequences would be unimaginable.

Xi Shiling shouted, "Retract the county town immediately!"

The Tang army soldiers didn't even have time to return to the barracks, and they didn't care about the 30,000 miners working in the mines. The three thousand Tang army turned around and ran towards Rulin County several miles away.

I have to say that Xi Shiling is indeed competent in escaping, decisive and determined, and will never drag it down. Just as Xi Shiling just left, the official road to the north was flying dust and horse hooves were sounding like thunder. A Sui cavalry was coming from a distance.

The mine suddenly exploded, and 30,000 miners were frightened and fled in scattered places. Some fled to the county town, some fled to the miner's camp, and some were quick to react and climbed up the mountain. The cavalry could not reach the mountain. The five mines, which were more than ten miles long, were all in a mess.

At this time, the three thousand cavalry vanguards led by General Sun Changle instantly rushed to the mine. The three thousand cavalry rushed into the barracks and captured several Tang soldiers who did not send troops due to illness.

Sun Changle pointed to the horse whip and asked, "Where has the army gone?"
Chapter completed!