Yanshan Mountain Range starts from Yanghe River in the west, reaches the sea in the east, connects with Taihang Mountain Range in the northwest with Guangou, and between the two mountains is the Hebei Plain, and Beiping is located in the northwest of the Hebei Plain. Beiping is the Beijing of later generations, and later generations will call the image of Beiping as Beijing Bay, because Beiping is surrounded by mountains on three sides, and the southeast area, but the water network is dense, and there are dotted with lakes and swamps, which are also natural obstacles to passage between Beiping and the North China Plain. Tongzhou City is located on the southeastern edge of Beijing Bay, so it is known as the east gate of Beiping.

Tongzhou has been set up in the Western Han Dynasty, known as Lu County, because it is located on the road from Beiping to Shanhaiguan and got its name, this road is flat, and there are few lofty mountains. Lu County was later renamed Lu County because it was close to Lushui, which was the North Canal of later generations, flowing through Tianjin, entering the Haihe River, and finally flowing into the Bohai Sea.

But it was not until the Yuan Dynasty and Kublai Khan set the capital in Beijing that the status of Tongzhou became important because of Cao Yun, but Tongzhou was not a military town at that time. In the first year of Hongwu, Xu Da conquered Tongzhou, and then occupied the capital, and then ordered Sun Xingzu to supervise the sergeant to build Tongzhou City, the city site is in the area of the old city in the west of the Luhe River, brick and porcelain outside, in the solid soil, around nine miles and thirteen steps, even the battlement wall is three feet high and five feet, open four city gates.

After Zhu Di raised his troops, he immediately sent people to attack Tongzhou, and Tongzhou Wei commanded Fang Sheng to surrender, Zhu Di ordered him to continue to guard Tongzhou, but for the sake of safety, Zhu Di found a companion for him, that is, Sun Yan. Sun Yan, a native of Fengyang, was an old man who followed Zhu Yuanzhang to cross the river, and later served as the guard of thousands of households in Yanshan, and Sun Yan had retired when Zhu Di raised his army. Zhu Di knew that he was old and reliable, so he and Fang Sheng cooperated to guard Tongzhou and guard the east gate of Beiping.

When Zhu Di went south to Hejian, he strictly ordered Fang Sheng and Sun Yan to guard the city to prevent Sheng Yong's sneak attack in Cangzhou, and not to slack off. Fang Sheng and Sun Yan were both veterans and cautious, so after winter, they ordered the sergeants to dig ice on the west bank of the North Canal to prevent the enemy from attacking the city from the south gate. This point can be said to coincide with the Baoding guard Meng Shan, Meng Shan also sent soldiers to dig the ice after the winter to prevent the moat from freezing, so that when the army of peace pressed the border, he tried to protect the city and insisted until Zhu Di's reinforcements arrived. In addition, the two also sent scouts to the surrounding areas every day to inquire about the news of Sheng Yongjun and Zhigu Guo Key; The four gates of Tongzhou are only open for one hour a day, and the city gates are closed at other times to prevent the enemy from sneaking attacks.

On the 28th of the first month, Sheng Yong's forward Zhang Hantian led 10,000 cavalry to attack Tongzhou City, although he killed all the scouts along the way, and hit Fang Sheng and Sun Yan by surprise, but in the end he was defeated and did not succeed in seizing the city, but Fang Sheng, Sun Yan and others were also shocked in a cold sweat. When he saw the banner under the city clearly, Fang Sheng blurted out: "It's Soap Banner, Sheng Yong will arrive soon, Brother Sun, we have to fly to Beiping immediately and ask for support." ”

"Well," Sun Yan stroked the beard on his chin and said, "What Brother Fang said is very true, but most of Beiping are old and weak, and they can't send reinforcements at all, so they have to wait for the prince to send reinforcements." Hopefully it's in time! Otherwise, relying only on the 5,000 elite soldiers in the city, I am afraid that it will not last long. ”

Fang Sheng was stunned for a moment, his tone was a little nervous, and he said tentatively: "Brother Sun, you want to surrender?" ”

"Hehe," Sun Yan smiled and said, "Brother Fang, we are all people who are close to the age of sixties, and it is worth it to be able to follow Wang Yejing." The prince is eloquent and strategic, and he will definitely be able to ascend to the great treasure, and we will all have the glory after death, what is there not to be satisfied with? ”

Fang Sheng paused for a moment and chuckled: "Yes, what Brother Sun said is very true. ”

"Yes, and we have already betrayed once, can we betray the prince again? Wouldn't that be a capricious villain? Even then, the court will not spare us, it is better to fight to the death, it is a big deal, what are you afraid of? ”

"Yes, what Brother Sun said is very true!"

Fang Sheng and Sun Yan looked at each other for a while, then laughed, put their arms out, and arranged for the city defense.

Sheng Yong led the army to Tongzhou two days later, and after listening to Zhang Hantian's report, Sheng Yong nodded, and did not reproach him, but ordered him to lead the cavalry to cruise around to protect the safety of the camp, and at the same time pay close attention to the movements of Beiping.

Since Zhu Yunwen appointed Sheng Yong as the right general of Pingyan, he increased his troops, Sheng Yong now commanded an army of 150,000 people, of which 40,000 people guarded the river with Xu Kai, Sheng Yong brought 110,000 people to garrison Cangzhou, including 20,000 cavalry, this time to the north, Sheng Yong took all the elite to the north, and strive to conquer Tongzhou in one fell swoop, and then based on Tongzhou, threatening Beiping. Sheng Yong is still relatively sober, he knows that it is impossible to conquer Beiping with 100,000 troops, but at least he can attract Zhu Di to come back, and as long as he holds Tongzhou, he can lock Zhu Di near Beiping, so that even if Baoding is conquered safely, the credit will fall behind him.

For peace, Sheng Yong was not only envious, but also very unconvinced. He didn't feel that he was worse than Ping'an, although he didn't dare to make irresponsible remarks about the emperor's appointment, but for General Pingyan, Sheng Yong still had to fight. He knows very well that this is the best opportunity since the founding of the Ming Dynasty, except for Feng Sheng and Wang Bi, two traitors, the Ming Dynasty will now wither the stars, only Wuding Marquis Guo Ying is left, so the emperor will vigorously promote young generals, and Ping'an, himself and Qu Neng are among the best, this time Pingyan is a touchstone, who can capture Beiping, capture and kill King Yan, you can be one step ahead, one step ahead, one step ahead, you will be ahead step by step, so that you can get more say in the future Mobei, Northwest and South battles. Thinking of this, Sheng Yong secretly cheered himself on, he must win; But at the same time, he also reminded himself that he must be careful, Ping An has been named Yong Yibo, but he is still white......

But when Sheng Yong saw Tongzhou City again the next day, he was shocked, because Tongzhou City had turned into a shining ice city. Fang Sheng and Sun Yan had already prepared, and they worked hard to hold Tongzhou and came up with this way to curb the winter siege. Last night, the sergeants were sent to pour water on the city walls, and overnight, the city walls were covered with a layer of "ice clothing", which would make it extremely difficult for the army to climb and attack the city.

Sheng Yong regretted it when he saw this, when he arrived yesterday, he should have attacked the city immediately, although he might not be able to attack it, but now that it is like this, it is almost impossible to attack the city.

But Sheng Yong did not give up, he used tiger squat cannons and rockets to attack the city on all sides, and soon there were many dead and wounded on the city, and the surviving soldiers were hiding behind the battlements and did not dare to show their heads, and the houses in the city were also on fire in many places, but Fang Sheng and Sun Yan had already prepared to organize the young and strong people in the city, concentrate on extinguishing the fire, and demolish the houses near the city wall to prevent the spread of the fire. It was early spring, and the night was bitterly cold, and the people in the city complained, and even froze to death. Fang Sheng and Sun Yan temporarily placed the old and weak who lost their houses to the government in the city, one to appease and the other to take hostages, because these old and weak relatives, especially the strong relatives, were sent to the city to help defend the city.

Fang Sheng and Sun Yan ordered the soldiers to water the city day after day. Sheng Yong attacked the city many times in vain, he looked at the fire in the city, as well as the ice on the city wall, regretted the abnormality, and at the same time was anxious, because every day passed, Zhu Di's return was more likely to be a point. And what he didn't know was that Fang Sheng and Sun Yan in the city were also very anxious, looking at the fewer and fewer houses in the city, their hearts were also full of despair. Now they no longer send messengers to Beiping, because they can't get out at all. Sheng Yong gave a strict order, if the messenger was released in any direction, the general in charge would be severely punished.

In order to break the deadlock, Sheng Yong sent a letter to Geng Xuan of Shanhaiguan and asked him to attack Yongping; At the same time, he reported the safety of Baoding, hoping that he would drag Zhu Di and buy him more time to conquer Tongzhou.

Of course, Sheng Yong also reported the battle report to the Jingshi, that is, Zhu Yunwen's hands.