Less than forty miles north of Xinghebao is Beishan, which is the border between the Tang State and the Khitan. The Tang army built a new castle on the bank of the Dongyang River in the northwest of Beishan, and stationed border troops to prevent the Khitans from crossing the border and plundering.

Kang Jiu, the original defender of the new castle, led his army to Shuofang, and now the new castle is also under the control of Weisai cavalry.

The northern city is not a lonely castle, so there is no way to defend it. There are also eleven tunbao around the new castle, one is to play a warning role, and the other is that if the Khitans attack on a large scale, these tunbao are also obstacles in their march.

There was a team of about 100 people stationed in each tunpu, and the surrounding area of the tunpu was their tun field, so these tun forts were distributed along the river.

The fields of these forts had to be irrigated by a large canal from the reservoir built on the west side of the new castle. The construction of the canal and the planning of the tuntian land is a technical task, and it is necessary to determine the height difference before the location of the tuntian land and the route of the trunk canal can be determined. The location of the tuntian land should not be higher than the bottom of the reservoir embankment, otherwise it will not be possible to divert water through it.

Experienced farmers measure the difference in height by extending their arms flat, holding up their thumbs, then closing one eye and looking into the distance along their arms. This method is empirical, and sometimes due to visual errors, it can produce large errors, and sometimes the results measured are just the opposite.

Liang Xing, the students who came out of Jinyang Academy, would make a simple level, and when they used this instrument to measure the height difference, it was obviously much more accurate. Li Cunshuo treated these "technicians" like treasures, and he was only asked to be in charge of the water conservancy camp and workshop of the two Tuntian Guards, and he would definitely not let these people participate in the actions of the cavalry troops.

In fact, since the Weisai cavalry moved to Xinghebao, the Khitan cavalry rarely crossed the border to harass, and Li Sifeng and Li Cunshuo seemed to have some reputation in the northland grassland. After hearing about the arrival of these two people, most of the nomadic grassland tribes in the area of Xiaobaishuiluo (Chagan Naoer) north of Beishan Mountain migrated to the area of Yuanyang Bo, and they were as far away as possible.

In a blink of an eye, it was August of the fourth year of the Republic, and the autumn wind in the north was gradually rising, and the weather was getting cooler.

The precipitation in the grassland of the dam is mainly concentrated in autumn, after a continuous autumn rain for several days, the turbid waves on the river surface of the Houhe River rolled, and the river rose to a position of only about less than a zhang away from the wooden bridge outside the gate of Dongshan Yingzhai.

Liang Xing and his family have been in the Weisai cavalry camp for two months, mainly working under Cao Yuanlang, who is in charge of logistics, and is responsible for the camp affairs and the management of the tuntian of Xinghe Fort and New Castle. The establishment of the Wesai cavalry was 3,100 regular soldiers, and with the addition of logistical auxiliaries, it reached nearly 4,500 men and nearly 4,000 military horses. In this large camp, only 1,000 cavalry are usually left on duty in turn, and most of the rest of the military horses are scattered in a few pastures distributed between Xinghe and Huairong Fort in the Dongyang River Valley.

The 300 pro-army under the main general Li Cunshuo has always followed the general to act together.

The reclamation of the northern land is extremely difficult, and some remote tunpu will occasionally be attacked by Khitan cross-border scouts, and there are often dangers. Immigrants from the interior are generally reluctant to go to such forts to garrison, so under normal circumstances, most of the troops in these remote forts are equipped troops. These convicts were also brave, and they were not very afraid of the small force of steppe cavalry, and sometimes even took the initiative to fight back.

When the autumn rain stopped, Liang Xing, according to the previous plan, took two military officers and a group of 12 guards to Beishan Fort in the northeast of the new castle to carry out surveying and mapping, and make preparations for the reclamation of the barren tuntian after the beginning of spring next year. Beishan Fort is located on the east side of the Shiya River, at the foot of the northwest of Beishan, and there is a cliff to the north. This open valley leads to the edge of the swampy meadows around Xiaobaishuiluo, and there is no dangerous terrain to defend.

On the top of the loess cliff, there is a huge beacon, which is guarded by soldiers sent by Beishan Fort in turn to be used as a vigilance. Due to its location on the border, Beishan Fort was stationed with two teams of more than 220 troops, commanded by a metropolitan colonel.

Liang Xing and his entourage went to Xincheng first, and came to Beishan Fort in the middle of the afternoon, and when they came to the gate of Tunpu, Qin Ming, the capital school, had already greeted them. "Welcome Liang to join the army, I am worried about not knowing how to plan the camp."

Liang Xing bowed his hand and said: "It's just that I am acting on orders, and I will accompany the inspection if I need to work, and some things are better to explain in person." ”

Qin Ming, the capital school, invited Liang Xing and his entourage into the fort, the fort is rectangular, about 300 steps longitudinal, less than 200 steps cross, the fort wall is rammed with loess, about one zhang more than one zhang high, about two steps wide, it can not be compared with the fort city. There are arrow towers built at the four corners of the tunpu parapet wall, and there is a tall watchtower about ten zhang high in the center of the fort courtyard, and the lower part is the tunpu military office and ordnance warehouse, and the upper part is used as an observatory.

There are also more than 30 rows of earthen houses made of earthen blocks in the courtyard of the tunpu, which are the residence of the military households stationed in the tun, and there are 12 earthen houses in each row, and there are about seven or eight military households.

Since he didn't eat lunch, Liang Xing was eating while listening to Qin Ming and Yang Fengnian, the Sihu of Beishan Fort, briefly describe the situation in Tunpu. Beishan Fort is a newly built Tunbao this year, but the fort was built, and the tuntian field was not started, and the food and salary were still supplied by the new castle. However, they were given more than 30 horses, more than 40 oxen, and 450 sheep for animal husbandry and later ploughing and transportation.

Cattle and horses graze around the fort, but the sheds are built in the tunpu and are driven back to the tunpu at night.

Beishanbao Tuntian is to use the water of the Shiya River to build a dam under the broken bank, use the river channel and depression under the cliff as a reservoir, and then divert water for irrigation. After lunch, Liang Xing was accompanied by Qin Ming and Yang Fengnian and climbed the towers in the fort together. The watchtower is more than ten zhang high, standing on the top of the building, you can look farther and observe the surrounding situation.

Due to the increase in precipitation in autumn, the surface of the Shiya River is also turbid, and the amount of water looks quite small.

The location of the fort here was chosen by the officials sent by the capital water superintendent, and the location was dozens of zhang higher than the slope under the stone cliff, and there was no problem in building a reservoir in the river valley on the other side of the stone cliff.

"After a while, I will go to the bottom of the stone cliff to inspect it, and first select the location of the river dam to be built, and then I can plan the direction of the main canal and the location of the wasteland to be reclaimed next spring." Liang Xing looked at the cliff in the northeast and said.

Qin Ming nodded: "The guards who joined the army will stay in the fort to rest, and you can bring someone to go with the army." ”

There are beacons on the top of the stone cliff near Beishan Fort and on the top of Heitou Mountain on the other side, which play the role of monitoring and vigilance, and if a group of Khitan cavalry appears nearby, it will be discovered from a distance. Wolf smoke is lit on the beacon, and the horn is blown to transmit the alarm to the rear in time.

On the other side, the Montenegro Beacon belongs to the jurisdiction of Montenegro Tunpu, which is also one of the Tunbao that Liang Xing is going to on this trip.