The wind on the sea is blowing gently to the north, although the fire in Yuguan City has been extinguished by Yan Pulihei's army, but the Jin people have always been committed to killing people and setting fires, where will they fight the fire? It was all grinding, and it didn't take long for the fire to gradually get smaller when there was nothing to burn.

Gao Yuan and Yang Keshi were at the top of the mountain, and not far below was the narrow valley of Jieshi Road. From above, there was a large area of Wansheng army in ambush on the mountainsides on both sides of the valley. Behind Gao Yuan, three huge speeding balloons had been deployed, but they were not yet fully swollen, and they were tied to the ground with ropes, no more than two feet above the ground. Next to each of the speedy cars stood two soldiers dressed in thick leather robes and hoods, carrying bows and arrows. In order to reduce the weight, the blades and armor were not carried.

Gao Yuan looked at the direction of Yuguan City from the top of the mountain, looked at the billowing smoke, and said regretfully: "It's a good Guancheng, and it will be burned if it is said to be burned." Da Lang is really good at it. If the city is lost, will it not be possible to set up a city on this stone road in the future? ”

"If that's not the case, how can you let Wanyan Lou Room chase after you with confidence?!" Yang Keshi shook his bearded head and said disappreciatively: "Besides, Yuguan City is just a small village, what's the pity?!" The city wall is two feet high, small and broken, what can it be used for? ”

"Listening to Da Lang's meaning, it seems that he wants to choose another place to build a customs city? Could it be here? Gao Yuan said to the stone Dao Nu in the valley below the mountain.

"I also heard what he said, this is not Yuguan City. I am originally from the Great Song Dynasty, and I don't know the geography here, is there still a fake in this Yuguan City? Yang Keshi asked puzzled. Zhou Nan came to Yuguan City on the first day, and said that this was not Yuguan City, which made Yang Keshi and Gao Yuan inexplicable, but then the three of them have been making arrangements for today's affairs for the past two days, and the two of them have no chance to ask Zhou Nan again.

"It's coming!" Gao Yuan stared intently at the northeast direction, and suddenly said, "There are still three or five miles away from here." ”

"It's time to go down. It's time to vent your anger this time! Yang Keshi said with a smile: "You don't have to spend your eyes here dryly." It's none of your business here, so let me go down! Gao Yuan sighed, and unwillingly followed Yang Keshi to ride down the mountain, ready to lead the troops to meet the Jin army, and muttered: "Da Lang is a good errand!" ”

This time, Zhou Nan came to Yuguan City, thinking about how to deal with the Jin army on the opposite side as soon as possible, so as to move forward, seize the location of the Shanhaiguan in the later world, and build a solid defense line there. Zhou Nan can now basically determine that the Yuguan City occupied by Gao Yuan should be the Funing and Changli areas of the later generations, and the real Yuguan, that is, the Shanhaiguan of the later generations, should be in the northeast of the current Yuguan City. However, the number of Jin troops here is the same as that of the Jin army opposite, and even slightly less than that of the Jin army. Fighting hard with the enemy Zhou Nan has always been the least like, so he has been thinking hard about countermeasures.

The general of the Jin Army on the opposite side is Wanyan Lou Room with the title of Victorious General, and Zhou Nan does not dare to be careless. The last time I was able to capture Yan Lou's room, the first thing I relied on was fraud, and after bullying Yan Lou's room, I didn't know how powerful my arrow was, so I knocked him out with an arrow. The second is that Wanyan Lou is proud of the enemy, and only brought 500 gold soldiers.

If you want to rely on fraud anymore, you definitely can't do it. When Zhou Nan rode a horse and Gao Yuan to explore the terrain around Guancheng, a gust of sea breeze blew, which made Zhou Nan's heart move.

"Brother Gao, you see that the wind is blowing to the north now, and it will definitely blow to the south at night!" Zhou Nan said firmly.

"Maybe! You and I have been together for more than a year, and I have never seen you know which way the wind is blowing. Gao Yuan said disbelievingly.

After the two returned to Guancheng, Gao Yuan said that the wind was blowing, but Yang Keshi said with a smile: "This time, Brother Gao, you are doomed." When marching and fighting, whoever is a great general must know astronomy and geography. Since I arrived in Yuguan City, I have been watching the weather every day, and it is strange here, the south wind always blows during the day, and the north wind blows at night. ”

Gao Yuan still didn't believe it, thinking that Yang Keshi and Zhou Nan were coaxing him. At night, sure enough, the wind direction changed to a north wind. Yang Keshi was born in the army, and he developed the habit of watching the celestial phenomena, and he already knew the change of wind direction every day, but Yang Keshi and Gao Yuan both wondered why Zhou Nan could know the secret of the change in wind direction on the third day after his arrival.

Zhou Nan didn't bother to explain it to the two of them. He was thinking that he wanted to use flying cars and explosive arrows to fight off the Jin soldiers. However, if you want to use a flying car, you have to consider the direction of the wind. The sea breeze with the smell of fish suddenly reminded Zhou Nan: in a small environment, the wind direction on the seaside is always fixed, and the wind will blow from the sea to the land during the day; At night, the wind blows from the land to the sea.

The reason is very simple, the temperature on land will be relatively high during the day, and the temperature of sea water will be low, due to the difference between the temperature of sea water and land, a thermal circulation will be formed, and the wind direction near the surface will blow from the sea surface to the land, which becomes the sea breeze during the day. At night, the temperature on the sea surface will be higher, and the temperature on land will be lower, and the wind direction near the ground will blow from the land to the sea, and the land breeze will blow at night.

Put it here, the sea is in the south, and the land is in the north, so naturally the south wind blows during the day and the north wind blows at night.

There is a fixed law in the direction of the wind, and the first way that Zhou Nan thought of was of course an aerial attack with flying cars and bombs. When Zhou Nan left Zunhua, the two flying cars were given to Gao Yuan and Yang Keshi; Later, when he was in Bianjing City, Gao Yuan sent someone back to bring three flying cars; Coupled with the flying car he brought back when he came back from Bianjing, and the two that were later made in Sanssouci Village, there were a total of eight flying cars. Two of them were the first batch of flying cars built by themselves in Gu'an City, and they were relatively large; The other six are all made according to the unified standards in Sanssouci Village, and the color, size, and function are the same. Zhou Nan was going to use the same six flying cars. In addition, Zhou Nan also asked people to prepare several boats, each of which can accommodate more than ten people. Zhou Nan selected fifty people who were proficient in water and could ship from among his pro-army guards and sent them to the ship. He also asked Yang Keshi to select a few people from among the locals who were familiar with the sea routes, and in the past two days, he was rowing a boat to practice advancing and retreating at sea. Of course, the Wang Shunzhou brought from Zunhua City was naturally arranged on the ship.

Yang Keshi and Gao Yuan couldn't guess what the boats were for, Gao Yuan wanted to personally take a flying car to kill the Jin people, but these six flying cars were all commanded by Zhou Nanlai, and Gao Yuan and Yang Keshi were only in charge of things on the ground, leading the army to intercept and injure the Jin army on the Jieshi Road, and leading the army to pursue when the Jin army fled.