(Xie: A wave of rewards from the Moshaocong brothers, Xie: I have thoughts about you, and a bunch of monthly passes for the two brothers.) ）

Wang Yuan's prediction was not wrong, the 70,000 troops of Gao Xianzhi of the Western Route Army marched from the small Bolu State to Tubo along the southern foot of Kunlun Mountain in just ten days, and they were blocked by the soldiers and horses of the Tubo vassal state.

The Pamir Plateau, where the four towns of Anxi are located, is lined with small states, and the conquest of these small countries has never ceased since the Tang Dynasty set up the capital protectorate in Anxi and hoarded heavy troops. These small countries had meager troops and were unable to stop the iron hooves of the Tang Dynasty, so they surrendered to the Tang Dynasty one after another and became subject countries conquered by the Tang Dynasty. But there are two small countries that are the henchmen of the Tang Dynasty, and that is the Great and Small Bolu Kingdom. These two small countries are located in the southern foothills of the Kunlun Mountains, on the main road leading to Tibet from the four towns of Anxi. The small Bolu country is in the west, the big Bolu country is in the east, one east and one west are blocked on the mountain pass, and the soldiers and horses of Anxi Town must first occupy these two small countries if they want to attack Tibet.

The Great and Small Bolu Kingdoms have always been subject states of Tibet and are protected by Tibet. Tubo Zampu married and kissed these two small countries, married the princess to the lords of the two countries, and sent troops and horses to assist them in defense, so that the two countries that were already on the high-altitude peaks and valleys were not trampled by the iron hooves of the Tang Dynasty.

In consideration of the strategic encirclement of Tibet, if the passage to Tibet from these two countries is not opened, the heavy troops of the four towns of Anxi will not be able to pose a threat to the Tibetans. With the four knots of Jiannan, Hexi, Longyou, and Anxi, the strategic encirclement formed against the Tubo people is missing an important link. In view of this, the Tang Dynasty sent troops several times to conquer the Great and Small Bolu Kingdoms and open this passage to the west of the Tubo Kingdom. However, the crusade against these two effects by Tian Renwan, Gai Jiayun, and Fumeng Lingcha, the three Anxi Jiedu envoys before Gao Xianzhi all ended in failure. The reason is very complicated, not that the soldiers and horses of the Tang Dynasty are not strong, not that the determination of the extremely successive Jiedu envoys is not enough, but because of the harsh climate and topography of the Pamir Plateau.

On the Pamir Plateau between the southern foothills of the Kunlun Mountains and the Himalayas, snow-capped peaks and canyons are lined with mountains. The little kingdom of Bolu was founded on this plateau and valley. The topography of the Green Mountains became a natural barrier for the small Bolu Kingdom to resist the Tang army. Lianyun Fort, at the western end of the small Bolu Kingdom, was defended by thousands of soldiers, keeping the soldiers and horses of the Tang Dynasty out of the country, making these brave and fierce generals of the Tang Dynasty fearful.

It wasn't until Gao Xianzhi that he changed his mind. At the beginning of the sixth year of Tianbao, when Wang Yuan led his army to fight with Nanzhao Kingdom in full swing, Gao Xianzhi led an army of 30,000 to launch a crusade against Xiao Boluguo. Gao Xianzhi is a native of Goguryeo, born to Gao Mada, handsome and fair-skinned, can be called a beautiful man in the army, if in the later life, this person can definitely be called a long-legged Oba for thousands of girls. It was this Gao Xianzhi, who looked polite and polite, who led 30,000 steps to ride across the incredible glacier of the Bole River. And this river is the glacier under Lianyunbao, the Tang army marched here several times before, but was blocked by this glacier, and Lianyunbao was lying on the mountain peak, the Tang army could not cross the river, let alone attack Lianyunbao, and had to return with a feather. However, Gao Xianzhi took advantage of the difference in water potential between morning and evening in the season, and relied on an accurate grasp of the environment, so that tens of thousands of soldiers and horses could easily cross this glacier. This river crossing was called by Gao Xianzhi as a river crossing where 'people do not wet the flag and horses do not wet the saddle'. Although he said it lightly, all those who know the inside story know how dangerous that glacier is.

After crossing the glacier, Gao Xianzhi sent strange soldiers to climb over the iceberg at an altitude of three thousand meters, and suddenly appeared in the rear of Lianyun Castle.

Since then, he has marched all the way, invaded the small Bolu country, broke the capital of the city of Abayue and the small Bolu country, captured the lord of the small Bolu country and the princess of the Tubo country alive, and escorted them to Chang'an. He also established the elder brother of the original lord as the new lord of the small Bolu country, and the new lord declared his submission to the Tang Dynasty and was a subject of the Tang Dynasty. Since then, the first gate to the western border of Tubo has been smashed by Gao Xianzhi.

After the capture of the small Bolu country, Gao Xianzhi did not rashly attack the big Bolu country, because he had limited troops and horses, although the terrain of the big Bolu country was not as difficult and dangerous as the small Bolu country, but he was embedded in the western border of Tubo, and the Tubo people increased a large number of troops to help garrison because the small Bolu country was conquered by the Tang Dynasty, so Gao Xianzhi did not act rashly. However, a month ago, a holy decree was delivered from Chang'an, thousands of miles away, and Gao Xianzhi immediately gathered the soldiers and horses under the command of the Anxi Jiedu to launch an attack on the western border of Tubo, which somewhat surprised Gao Xianzhi. In Gao Xianzhi's view, the time is not yet ripe to attack Tibet, and the risk is too great.

However, the king's order could not be disobeyed, Gao Xianzhi could only immediately assemble the whole army in the territory of the small Bolu country, and the army of 70,000 began to march on March 15, and a few days later attacked the territory of the big Bolu country, aiming at the capital of the Great Bolu country, Bodhisattva Lao City. When the army from the western border of Tibet heard the news, 30,000 troops went to the city of Bodhisattva Lao to assist in the defense, blocking Gao Xianzhi's army of 70,000 under the city of Bodhisattva Lao.

Gao Xianzhi understood that if he could not take the city of Bodhisattva Lao, he would not be able to enter the western border of Tubo, let alone attack to the east, and threaten the capital of Tubo according to the requirements of the holy decree. After some preparations, Gao Xianzhi launched an attack on the city of Bodhisattva Lao.

This battle was extremely bloody, Gao Xianzhi made up his mind to capture the city, and the soldiers and horses of the Great Bolu Kingdom and the Tubo soldiers and horses of the Bodhisattva Lao City also swore to defend to the death, and the two sides fought for two days and two nights. While Wang Yuan's soldiers and horses were still struggling in the desert, Gao Xianzhi broke through the Bodhisattva Lao City at the cost of 20,000 people. More than 10,000 Tibetan soldiers and horses defending the city retreated to the east, because they did not want to fight to the death with Gao Xianzhi, who had far more troops than themselves. They wanted to preserve their strength, fight with the army from the western frontier reinforced by the Tubo State, and fight to the death on the road of Gao Xianzhi's attack on Tubo.

Although Gao Xianzhi captured the city of Bodhisattva Lao, he was not happy. This was only the first battle with the Tibetans, and 20,000 soldiers and horses were killed and wounded, and there were countless fierce battles to be fought after that, which cast a dark cloud over the road ahead of his march. But in any case, after the victory of this battle, the Great Bolu Kingdom basically lost the power of resistance, and the army could drive straight into the western border of Tibet, and the first roadblock was cleared, which is still worth celebrating from a strategic point of view. Gao Xianzhi knew that there were other Jiannan Army and Longyou Hexi Coalition Army to attack Tubo again, and he had never pinned his hopes on others before, but after this battle, after learning the fierceness of Tubo's soldiers and horses, he desperately hoped that the soldiers and horses of the other two roads would quickly exert pressure to relieve his pressure. Especially the Jiannan Army, if the Jiannan Army could storm from the east and form an east-west offensive with himself, it would greatly reduce his pressure, although he never thought that Wang Yuan could do this.

Except for himself, Gao Xianzhi had no confidence in anyone, let alone Wang Yuan, who was said to have ascended to the throne by Yang Guozhong's promotion.

……

On the sixth day of the fourth month, after 20 days of long-distance marching, most of the Jiannan Army finally left behind the desert that stretched for nearly 200 miles. When they saw the Gobi hills on the edge of the desert and the land of great rivers and forests, all the soldiers of the Jiannan Army had a sense of being separated from the world. Walking in the monotonous and scorching desert for more than 20 days is a great torture for people's psychology and physiology, and when they see the meadows, hillsides, woods, and rivers, everyone can't help but cheer.

At this moment, a small grass, a wild flower, a piece of soil, a pond and other ordinary things seem to be full of emotion in the eyes of everyone. But they didn't have time to sigh, their goal was to capture the Yak City as soon as possible, and it was on the top of a hillside on the north bank of the Yak River. Although the hillside is not high, the city is condescending, and it gives people a coercive momentum.

The army arrived at the foot of the Yak City the next morning, and learned very early that the Tubo soldiers and horses attacked from the desert by the Tang Dynasty had already made all preparations. The walls were raised in height in a matter of days, and the moat was dug a foot deeper. On the hillside outside the city, there were thorns and thorns, pits, horses and other things, and they were not afraid to use any means that could block the Tang army's attack.

The 10,000 defenders of the city were confident that they could withstand the Tang army's onslaught, and they only needed to delay for a few days before reinforcements arrived. The letter asking for help had been sent a few days earlier, and if there were no accidents, reinforcements would arrive within a few days.

The Tang army camped on the slopes of the hill outside the city, and after seeing the enemy's layout and terrain, all the generals found it very tricky. Yak City is easy to defend and difficult to attack, and it may take a lot of effort to capture this city. Wang Yuan didn't want to linger here for too long, so he decided to use his killer weapon. That big killing weapon has not yet been officially used in battle, and Yak City happens to be the first object to be used, although it is a bit overkill to do so, but in order to buy time, Wang Yuan can only do this.