The invasion of the Tang Dynasty by Tubo was mainly from five directions, Anxi, Hexi, Longyou, Jiannan and Nanzhao.

At present, there are 10,000 troops in Jiannan Jiedu Mansion in name, but in fact there are only less than 7,000 troops in the army, and the army is vacant up and down, although the Jiannan Army is only less than 7,000 people, but they are not the descendants of the eunuchs, they only belong to the border army of the Southern Tang Dynasty, and the treatment is much worse than that of the Shence Army, and the monthly salary is only 600 yuan, and the food is also very poor, and the morale is generally low.

In fact, 7,000 people are simply not enough to defend so many posts and cities, and Wang Qingyang, the commander of the Jiannan Army, does not care too much, and only deploys the army at a few important strategic nodes such as Yazhou, Zhezhou, and Wenzhou.

In the afternoon of that day, in the mountains and mountains west of Yazhou, a Tibetan army of more than 25,000 people appeared, and this Tibetan army was led by Shang Dongzan, a new star general of Tibet.

In recent years, great changes have taken place within Tibet, under the auspices of the master Padmasambhava, Tibet fully converted to Buddhism, last year sent troops to Tianzhu, Shang Dongzan led 20,000 Tubo troops to sweep across both sides of the Ganges, the small countries along the coast have surrendered, and in one go to attack the capital of Magadha, not only to seize the Buddha's relics, but also to obtain a large amount of wealth and slaves.

The war dividends obtained from this expedition to Tianzhu made the originally weak Tubo national strength strong all of a sudden, the warehouses were full of wheat, the fields were full of countless cattle and sheep, millions of Tianzhu people were plundered into slavery, they grazed and farmed, so that countless Tubo young and strong men were liberated from labor and joined the army, and the Tubo army increased from 50,000 to 1440,000 at once.

After his strength was restored, the ambition of Tubo Zanpu Trisong Detsen burst out again, and he asked the great minister Shang Jiezan to formulate a plan to conquer the Tang Dynasty in the east.

Shang Jiezan's eyes were fixed on the Southern Tang Dynasty, he saw the weakness and unpopularity of the Southern Tang Dynasty, just at this time, the young emperor of the Southern Tang Dynasty died, and the internal situation was unstable, Shang Jiezan seized this opportunity and ordered his younger brother Shang Dongzan to lead an army of 25,000 to invade the Southern Tang Dynasty.

At the same time, he deployed 20,000 troops on the front line of Longyou, on the one hand, to contain Guo Song's army, and on the other hand, to prevent the Longyou army from encircling Wei and saving Zhao to solve the crisis in Chengdu.

As the main general of the Eastern Expedition, Shang Dongzan's first target was Yazhou City, that is, Yandao County, and by capturing Yazhou City, they would have a foundation for attacking Chengdu, and at the same time open the western gate to the rich Chengdu Plain.

The army was marching eastward along a river, with mountains and forests on both sides, and at this time, Shang Dongzan saw that the eastern sky was white, and it was still nearly eighty miles away from Yazhou, so he ordered: "Camp and rest on the spot!" ”

After a night of marching, the soldiers were exhausted, and they all lay on the river to wash and drink water, and the adjutant general Non Dosang stepped forward with several generals and asked: "General, why don't you go to Yazhou in one go?" I believe that the Tang Army in Yazhou will definitely flee from the wind. ”

Shang Dongzan patiently explained to him: "We don't have siege weapons, we can only rely on surprise soldiers to win, although the morale of the Tang army is low, it is likely to flee from the wind, but there is another possibility, they defend the city, Yazhou City is tall and strong, once the other party defends the city, we will be in big trouble, so we must be cautious, night and day, can not be discovered by the enemy." ”

Shang Dongzan's explanation convinced several generals and saluted one after another, "What the general said is very true, we understand!" ”

The generals went to rest, but Shang Dongzan was a little worried, wondering if the people he sent could find the Tubo spies planted in Yazhou City?

..........

Yazhou City is a big frontier city, with a large population, nearly 100,000 people, a lot of border trade is carried out here, commerce is quite prosperous, there are many Tubo people, Qiang people, Tuyuhun people and Nanzhao people opened shops, the personnel structure in the city is also relatively complex, but although the Han people account for the majority, but there are also a large number of other ethnic groups living here, with the Tubo and Qiang people being the most.

As the west gate of the Chengdu Plain, the strategic location of Yazhou City is also very important, for a hundred years, Jiannan Jiedu Mansion has been stationed here heavy troops, although now Jiannan Jiedu Mansion is seriously weakened, but the garrison of Yazhou is still as many as 3,000 people, almost accounting for the entire Jiannan Jiedu Mansion at present, forty percent of the troops.

Similarly, as a defensive frontier town, Yazhou City was built tall and strong, easy to defend and difficult to attack, and the main general was called Zhang Meng, and the official was appointed as General Sanpin Yunlu, who had just arrived last month.

Zhang Meng is not a general of the Jiannan department, but a general of the Shence Army, and he is also one of the thirteen righteous sons of Dou Wenchang, known as the Thirteen Taibao, he ranks third.

As a high-ranking military general from the third grade, he went to this remote place in Yazhou to be a guard, naturally there is his reason, there is a lot of oil and water here, although the actual defenders of Yazhou City are only 3,000 people, but the military department is registered with 5,000 people, and the military department is according to 5,000 people to distribute military salaries and food, there are 2,000 people in it, which is a veritable fat shortage.

Although a border soldier only has 600 yuan a month, he has 1,200 yuan of oil and water a month, plus he can sell excess military food and materials, there is no problem with 1,600 yuan a month, half of the filial piety Dou Wenchang, and then distribute the points to other generals, he himself can earn 500 yuan a month, and 6,000 yuan a year.

Zhang Meng patrolled back and forth in the city, he looked at the main road in the city, East Street, there were shops on both sides, people came and went, quite lively, and there were caravans leading mules and horses passing by.

Zhang Meng is planning a piece of land, a pharmacy opened by a Tibetan businessman, this land is big enough, if he takes it down and builds a restaurant, won't the wealth come in?

"Damn the Tibetans!" Zhang Meng scolded viciously.

Zhang Meng made up his mind, and in the past few days, he wanted to find an excuse to be killed by this Tibetan shopkeeper, saying that he was a spy in Tubo.

........

If Zhang Meng knew that the Tibetan merchant he was going to slander as an enemy was really a Tibetan spy, he didn't know what he should think.

This shop is located in the middle of East Street, is a Tubo medicine shop, the store is called Yaoling, opened in Yazhou City for nearly 20 years, covers an area of about ten acres, is the largest store in the entire East Street, and the location is excellent, almost the center of the entire Yazhou City, no wonder the main general Zhang Meng had an idea about it.

The owner of the shopkeeper is a forty-five or sixteen-year-old Tubo man, named Mangjia, who is very kind, he gives himself a Chinese name, called Li Mang, but the other shopkeepers call him Uncle Mang.

Mangjia mainly does medicinal materials and fur business, medicinal materials from the plateau are very popular in the Bashu area, his business is good, there are many fixed customers, every year after the summer solstice, from the plateau to transport a large number of Cordyceps, gastrodia, fritillary, palm ginseng, snow lotus, Ganoderma lucidum, antelope horn and other medicinal materials and fur, at this time, his customers will also come from all over the country to purchase, after the medicinal materials are sold, he will purchase a batch of living materials to send back to the plateau, 20 years has been like this.

Because of the seasonal factor, his usual business does not look good, and the store is always deserted, except for Mangjia's swarthy face.

Mangjia was actually a Tibetan official who had been ordered to set up shop in Yazhou for twenty years, and had been collecting intelligence on Bashu, while also smuggling some contraband to the plateau, such as pig iron.

At noon, two young Tibetans came to the pharmacy, and they shook a bronze medal in front of Mangjia's eyes, Mangjia's face suddenly changed, and he hurriedly took the two to the back room.

The Tubo spies led by the Tubo spies put the bronze medal on the table and pushed it to Mangjia to take a closer look, Mangjia looked at it carefully, it turned out to be the bronze medal of the army, he immediately realized that there was going to be a military operation, and hurriedly asked: "Did Zampu decide to capture Ya'an?" ”

The Tubo spy said: "We are the spies of General Shang Dongzan, the Tubo army is less than a hundred miles away from Yazhou City, and it will be killed tonight, General Shang said that you have prepared, let us come over and see, what kind of preparation is it?" ”

Mangga nodded and sighed softly, "I have indeed been preparing for several years, just waiting for this day, you come with me!" ”

He closed the shop, took two spies to the back yard, left through the back door, and walked through a few alleys, until he came to the west wall, and he walked into a rather dilapidated courtyard, which was inhabited by several of his fellows, which were the dormitories of the pharmacy, and there were six or seven rooms in total, the last two of which seemed to be pressed against the city wall.

Mangga took the two spies all the way to the back room, which had no windows and was pitch black, and he lit a lamp, and the two spies saw it, and saw that the room was empty, and there were two large wooden cupboards against the wall.

Manga put the oil lamp on the table, beckoned to a few of the men, and everyone pushed the wooden cupboard together, and the wooden cupboard parted on both sides, revealing a large black hole, six feet high.

"It's ......" both spies froze.

"This is the city wall, which we hollowed out, and the top is covered with wooden planks, and at the end of the road is the outermost city brick."

Mangga picked up the oil lamp and walked in, inside were thick planks and thick wooden pillars, and the dirt between the cracks could be faintly seen, and he walked to the end, and there was a wall in front of him, and he patted the wall, "These wall bricks are actually loose, and it only takes a quarter of an hour for us to tear out a big hole." ”