The western and southern regions of Goguryeo almost all fell into the hands of the Tang Dynasty, especially after the fall of Pyongyang, even the stubborn Beisha City surrendered to Zhang Liang's army, and the eastern part was defeated by the Silla people.

Most of the northern part is mountainous, and the natural environment is relatively harsh, for example, although the vicinity of Marudu Fortress is the birthplace of Goguryeo, but later most of the Goguryeo people moved to the vicinity of Pyongyang, so compared to the south where Pyongyang is located, the northern part of the country deserves to be much more desolate.

Qin Qiong led an army of 30,000 all the way to the direction of Marudu City, although there were many difficulties on the road, mainly because the road was too difficult to walk, especially now that it was autumn, not only did the weather begin to get colder, but it also rained occasionally, although the rain was not heavy, but it was very cold, and it felt like the whole body was going to be numb with frost when it fell on people.

However, although the road is not easy to walk, at least there are no decent enemies, there are a few small cities on the road, but the Goguryeo people in the city saw Qin Qiong's army, and surrendered without any resistance, and from these small cities, I also heard that Quangai Suwen did pass here some time ago, and now it should have arrived at Marudu City.

Got the exact news of Quangai Suwen, Qin Qiong discussed with Li Xiu and Cheng Yanjin, and then accelerated the speed of the march again, and in late July, they finally came to the Yalu River again, it is worth mentioning that the city of Marudu is on the west bank of the Yalu River, and when Li Xiu lived in his last life, the city of Marudu belonged to the urban area of Ji'an, Jilin Province, across the river from North Korea.

However, compared to Bogoukou, Marudu Castle belongs to the upper reaches of the Yalu River, the river is not very wide, and the terrain on the opposite side is very open, looking across the river to the opposite side, you can see a medium-sized city at a glance, but this city is not Marudu City, but another domestic city of Goguryeo, and it is also the earliest capital of Goguryeo.

And in the northwest direction of the domestic city, there is a continuous mountain range, one of which is the Marudu Mountain, and the Marudu City is also built on this mountain, the whole city occupies almost the entire mountain, the city wall is also built according to the mountain situation, the terrain is very dangerous, although it was destroyed in the war twice, but later after the restoration of Goguryeo, it is still a natural hazard.

This crossing of the river is very smooth, the river is not wide, the terrain is not dangerous, if Quangai Suwen wants to intercept, it is necessary to send a large number of troops, and now he only has more than 30,000 remnants of the defeated generals, and he does not dare to fight with the Tang army on a large scale at all, and now they are all cowering in the domestic city and the city of Marudu.

After crossing the Yalu River, Qin Qiong immediately commanded the army to camp in the south of the domestic city, and the Goguryeo people at the head of the city were also very nervous, and after arranging the camp, Qin Qiong, Cheng Yanjin, and Li Xiu went out of the camp together, and climbed a nearby hill to observe the terrain around the domestic city.

The whole city of China is surrounded by mountains, but there is a small plain in the mountains, which is also the origin of the Goguryeo people, and the plain is full of cultivated fields, but now they have been harvested, and it is estimated that there is a considerable amount of grain stored in the domestic city and the city of Marudu, so it is definitely not enough to besiege alone.

Li Xiu held a telescope in his hand and carefully looked at the domestic city, although this city does not look very big, and even the city wall is not very high, at least it cannot be compared with Pyongyang City, but there is one place that makes Li Xiu frown, because the shape of the domestic city is very strange, the shape of this city is not large, and it suddenly extends out in the back, so that the domestic city is connected with the mountain behind, so that the entire city and the mountain are nestled together.

Originally, it was not strange to build a city on the mountain, but it was the Marudu Mountain that was close to the domestic city, and the mountain was very steep, and the road up the mountain was in the domestic city, in other words, if you wanted to attack the Marudu City, you had to lay the domestic city, and even if the domestic city was laid, the army in the city could also withdraw to the Marudu City, plus the mountain road was very dangerous, let alone attacking the Marudu City, even if it was not easy to go up the mountain.

"Marudu City is so steep, Wu Qiu Jian was the one who broke through this natural danger at the beginning?" Cheng Yanjin looked at the Pill Capital City in the distance for a long time, and finally took a long breath, although he had heard that Pill City was easy to defend and difficult to attack, but when he saw it with his own eyes, he found that this city was even more difficult to fight than he imagined.

"On the way here, I have collected some news about Marudu Castle, it is said that because Marudu Castle has been breached many times, so later the Goguryeo people destroyed some of the roads up the mountain in Marudu Mountain, this mountain is already dangerous, and there are not many roads up the mountain, and now there is only one road left in the domestic city, and it is very dangerous, and what's worse is that there is water and food on Marudu Mountain, which is enough for them to support until the coming of winter." Li Xiu explained in a low voice at this time.

"This is indeed bad news, but it is not completely impossible to take down the pill capital city, I remember that the history books once recorded that more than two hundred years ago when the Yan King Murong Huangguang attacked the pill capital city, there was no progress at the beginning, and then he set fire to the mountain in a fit of rage, and the forest on the pill capital mountain was dense, and the result was that the houses of the pill capital city were burned at once, and finally Goguryeo suffered countless casualties, and the pill capital city was also destroyed in that fire." At this time, Qin Qiong also spoke, although setting fire to the mountain will hurt the heavens and peace, but there is no mercy on the battlefield, not to mention that this is not the Tang Dynasty, and he doesn't have to worry about accidentally hurting the people.

"Uncle Bao, take a closer look, the trees near Marudu City seem to have been cut down, I'm afraid you won't be able to burn the other party's city if you want to!" However, as soon as Qin Qiong's words fell, Cheng Yanjin pointed to the Marudu City Road on the top of the mountain.

Hearing Cheng Biting Jin's words, Li Xiu and Qin Qiong also hurriedly raised their binoculars to take a closer look, and finally found that the trees near Marudu City had been cut down, leaving a wide isolation zone, but because of the dense forests on the mountain, if you don't look carefully, you really can't find it for a while, it seems that the Goguryeo people have also learned a lesson, even if the Tang army set fire, they can't burn the pill capital city.

"This is terrible, if the fire attack is ineffective, then we can only honestly start the attack from the domestic city." When Qin Qiong saw the isolation zone outside the pill capital, she couldn't help frowning and said.

"The domestic city is not difficult to fight, although the Maru Capital Castle can send reinforcements, but with the defense of the domestic city, it should be easy to blow up the city gate with gunpowder, and after controlling the domestic city, it is not too late to consider attacking the Maru Capital Castle." Cheng Yanjin said again at this time, no matter what method is used, it is better to lay down the domestic city, otherwise he will not even be able to find the way up the mountain.

Hearing Cheng Biting Jin's words, Qin Qiong also nodded, but at this time he found that Li Xiu had been silent, which made him ask curiously: "Donkey, I don't know what you can do?" ”

"I can't talk about the method yet, but I have a vague idea, and just like General Cheng said, it's not too late for us to knock down the domestic city first and then make plans." Li Xiu raised his head at this time and said with a smile, although Marudu City has made a lot of defensive preparations, but through some technical means, there may not be no way to overcome it, it depends on what they do.

Seeing that Li Xiu didn't elaborate, Qin Qiong and Cheng Yanjin didn't ask again, and then the three of them carefully observed the situation in the domestic city, and there were also people in the camp who raised a hot air balloon and began to observe the domestic city under high supervision, and soon the situation in the city was reported, and Qin Qiong and Cheng Yanjin also began to study the plan to attack the city.

At the same time, at the head of the domestic city, Quan Gai Suwen and his son Quan Nanjian are also looking at the Tang army's camp, although it has only been more than a month since the last time Pyongyang fled, but Quan Gai Suwen has aged a lot all of a sudden, and there are a few more wrinkles on his originally resolute face, and there are a lot of gray hair on his temples.

"Father, it seems that the number of the Tang army does not exceed 30,000, and we still have a little advantage in terms of troops, and with the help of city defense, there should be no problem in holding here." Quan Nanjian looked at the Tang army's barracks for a while, and then said to Quan Gai Su Wen with some excitement, they had guessed that the Tang army occupied Pyongyang City and would definitely divide its troops to defend it, but now it seems that this is the case.

"Haven't you yet comprehended the combat effectiveness of the Tang Army, even if the other party only has 10,000 people, you must not underestimate it, during this time, you should hurry up and transfer the materials of the domestic city to the pill capital city, and try not to leave anything behind!" Quan Gai Suwen reprimanded with a solemn face.

"Father, do you really want to abandon the domestic city?" Quan Nanjian couldn't help but ask a little unwillingly when he heard his father's words, after coming to the domestic city, Quan Gai Suwen made a decision to abandon the domestic city and concentrate all his troops to guard the pill capital city, which made Quan Nanjian also very puzzled, after all, although the domestic city is not as good as Pyongyang in defense, it can also be used to consume part of the Tang army's strength.

"There is almost no danger to defend the domestic city, and it can't be defended for long by relying on the city wall alone, and I forgot that the Tang army has gunpowder, and no kind of city wall can stop them, so dividing troops to guard here will only consume our strength, it is better to concentrate all our forces in Marudu City, so that our chances of victory can be greater!" Quangai Suwen said without hesitation.

In fact, there is another reason why Quangai Suwen did not say, that is, he led more than 30,000 people to flee here from Pyongyang, and the people were already panicked and had no heart to fight.