In fact, the mission assigned by Cao Liang to Deng Ai was not that strict. This attack, including the attacks of the Central Army against Pubanjin and the Right Army against Wuguan, were all tentative. Cao Liang just wanted to test how strong Guanzhong's defense ability was.

Of course, if the defense line of Tongguan was like paper, Cao Liang would not mind Deng Ai's troops taking down Tongguan, entering Guanzhong, and directly attacking Chang'an.

But if the Sima Army's defense was particularly tenacious and the defense line was as solid as a rock, Cao Liang did not recommend that the Bingzhou Army launch a strong attack. After all, such an approach would hurt one thousand enemies and would damage eight hundred of them. There was no need for the Bingzhou Army to fight to the end with the Sima Army.

Today, Sima Jun is like a wild beast forced into a desperate situation. Although it is in a worrying situation, it has not lost its ability to fight. When it is on the verge of despair, it will only make it even more crazy.

Therefore, Cao Liang's order to Deng Ai was to test the softness and hardness of the Tongguan defense line. If it is easy to take, take it, and if it is not easy to take, stop it. Anyway, the Sima family is already at the end of the road. Given Cao Liang some time, there is always a way to solve it.

So Deng Ai did not send all the main force to attack Tongguan, but simply sent a large number of catapults and crossbows to launch a series of bombardment on Tongguan.

However, it is obvious that such an attack did not work very well. After all, in order to strengthen the defense of Tongguan, Sima Army specially strengthened the city walls of Tongguan and replaced the original rammed earth city walls with stone walls. In this way, the solid performance of the stone city walls was greatly improved by many times. They could handle such sharp siege weapons as catapults.

The battle situation in Tongguan was in a stalemate, and the war dragged on for several months, but the Bingzhou army seemed to have no intention of withdrawing its troops, and the double convenience was consumed in this stalemate.

Not only Tongguan, but also Wuguan and Pubanjin defense lines were also in a hurry. This time, the Bingzhou army's attack was comprehensive, with troops divided into three groups and launched an attack on the three major passes in Guanzhong. The entire Guanzhong defense line was tight, and the troops everywhere were too short to take care of themselves, so Hu Fen could not count on other troops to come to rescue. Faced with Deng Ai's attack, he could only support himself, and it would be a day to survive.

Fortunately, Deng Ai's attack was not strong, and Hu Fen was not under much pressure. After several months of stalemate between the two sides, Hu Fen's confidence seemed to have returned. It seems that the Bingzhou army is not invincible.

The steep mountainous terrain left the most powerful cavalry of the Bingzhou Army without any place to use its power. After strengthening the Tongguan Pass City, it could completely withstand the attack of the catapult. Without these two powerful weapons for attacks, the Bingzhou Army would no longer have its fierce minions, and Tongguan became a hard bone that could be cracked.

Hu Fen couldn't help but sigh that Sima Lun had foresight! After retreating to Guanzhong, Sima Lun ordered the reconstruction of Wuguan and Tongguan. He spent a lot of manpower and material resources to rebuild all the city walls on Tongguan and east of Wuguan with stones, and increase them. The city walls built in this way were extremely solid, and could completely resist the attack of the stone casting cart, and became the foundation for their lives.

Otherwise, the original rammed earth city wall would not be able to withstand the catapults of the Bingzhou Army. Once the wall was broken, the defense line of Tongguan would be in vain.

The demon is one foot taller and the road is one foot taller. No matter how powerful the catapult car is, it still has something to restrain it. However, the cost is still relatively high. However, compared with the safety of Guanzhong, no matter how much the price is, it can be afforded.

Hu Fen originally thought that the situation could continue like this. Anyway, they were the defensive side, and the pressure was far less than that of the offensive side, and if it was consumed, the situation would be beneficial to them. After all, the Bingzhou army would have a day that could not be supported and then retreat.

But what happened in Chang'an caught him off guard and was helpless. In one day, the emperor Cao Mao and Sima Shi were assassinated one after another. Then, Sima Zhao deposed Wei and proclaimed himself emperor, and changed the country's name to Jin.

This series of accidents shocked everyone. Just when the situation in Guanzhong was in danger, Sima Zhao suddenly made so many tricks, which was not a good sign.

Although Hu Fen was just a guard at the side, he also knew that stability is an urgent matter to suppress everything. Any changes and turmoil in Guanzhong would be a fatal blow to the Guanzhong defense line. He was deeply worried that the situation in Guanzhong had already developed in an uncontrollable direction.

After Sima Zhao ascended the throne, he was granted the title of ministers, and Hu Fen was also named General Zhennan. The imperial edict was passed to Tongguan, but Hu Fen could not feel any joy on his face. After all, he was not Sima Zhao's direct line. Hu Fen has always been obedient to Sima Shi. Sima Shi handed over power to Sima Lun, so Hu Fen naturally obeyed Sima Lun.

But unexpectedly, Sima Zhao would suddenly become the emperor and become the emperor. Although Hu Fen was promoted, he was not Sima Zhao's confidant after all. In Tongguan, Sima Zhao was considering replacing people?

After Hu Fen accepted the imperial edict, he sent someone to Pubanjin to contact Sima Lun. He wanted to know Sima Lun's true thoughts. Although Sima Zhao succeeded to the throne as emperor, all the power of military power was still in the hands of Sima Lun. If Sima Lun raised an army to resist, Hu Fen would not mind leading his troops to follow him. He would rather be the main person than respect Sima Zhao as emperor.

But there seemed to be no movement on Sima Lun. He also accepted the title of King Zhao and did not take the next step. He also wrote a letter to Hu Fen and Zhoutai, asking them to defend the defense line. They must not affect the morale of the defense line because of Chang'an's dynasty, so that the Bingzhou army can take advantage of the opportunity.

Hu Fen was helpless, after all, Sima Lun did not act rashly, how could he dare to have any ideas?

In fact, Hu Fen can understand Sima Lun. Although Sima Lun now holds more than 100,000 troops in his hand, he was basically dragged on the defense line from Wuguan to Pubanjin by the Bingzhou army, and he could not draw much force to deal with Sima Zhao.

Moreover, Sima Zhao was also pinching his lifeline of food and grass. If Sima Lun raised an army, Sima Zhao could cut off the supply of food and grass at any time. It would be fine if Sima Lun could take Chang'an in a short time. Once the war was unfavorable, the entire army would have the risk of food being cut off, and the consequences would be unimaginable.

Therefore, from the perspective of the overall situation, Sima Lun still succumbed to the point. After all, Sima Lun was afraid of being a weapon. Once he led his troops to resist, everyone in the Sima family would suffer.

But Sima Zhao obviously would not feel at ease with Sima Lun. Soon, he still attacked the eastern defense line.
Chapter completed!