Lü Wende's Black Carbon Army, with Lü's relatives and Huaixi soldiers as the main body, later absorbed the elite of Hubei, and gradually grew in the long war, becoming one of the three most famous military groups in the Song Dynasty. Lu Wende led the army to Hunan, Guizhou, Sichuan and other places, and made great contributions and was promoted repeatedly. For ten years, from the first year of Taiping to the fifth year of Anguo, Wende served as the highest military and political governor in the Huaixi Hubei region, resisting the Mongol invasion head-on. In the seventh year of Baofu (1259 AD), Lü Fuzhou and Lü Wende's younger brother Lü Wenxin died in battle at the same time. In the second year of Taiping (1261 AD), Liu Quan, a general of the Song Dynasty, surrendered to Mongolia because he was squeezed out by the Lu group. Taiping three years, into the Feng Kaifu Yi with the three divisions. In the seventh year of Anguo (1270 AD), Lu Wende died in the midst of illness, and he was posthumously crowned as the "King of Heyi County" in June of this year (1272 AD).

After Lü Wende's death, Lü Wenhuan became the leader of Lü's army, that is, during this period, the focus of the Mongol army's offensive was changed to Xiangfan, realizing the transformation from the Sichuan-Shu battlefield to the Jingxiang battlefield. The Mongolian general Shi Tianze built a long siege in the west of Xiangfan, and built a city in the south of Da Xian Mountain and Hutou Mountain, connecting the forts, completely cutting off the connection between Xiangyang and the northwest and southeast, making Xiangyang an isolated city. During this period, the Mongolian army built more than 10 castles on the periphery of Xiangfan, established a stronghold of long-term siege of Xiangfan, completed the strategic encirclement of Xiangfan, and was in a strategic advantage, in order to break the siege of Lumen and Baihe of the Mongolian army, Lu Wenhuan personally led the defenders of Xiangyang to attack the Mongolian army, but was defeated by the Mongolian army, and the Song army suffered heavy casualties.

After Xiangyang was besieged, the prime minister of the Song Dynasty, Jia Nidao, tried his best to rescue and sent the Song general Zhang Shijie to lead an army to fight against the Mongol army besieging Fancheng, but was defeated by the Mongol general Ashu. Jia Rudao also sent Xia Gui to lead the army to rescue Xiangyang, but was ambushed by the Mongol army and the Han army, and the army was defeated in Huweizhou, losing more than 2,000 people and 50 warships. Subsequently, the Mongol army built a siege around Xiang and Fan, blocked the Han River, and controlled the water and land to rush; At the same time, build warships and train sailors; and repeatedly defeated the Southern Song reinforcements. Jia Yidao appointed Li Tingzhi as the ambassador of the Jinghu system, supervising the teachers and aiding Xiang, and repeatedly fought unfavorably. But the reason is that Fan Wenhu, the son-in-law of another general, Lu Wende, was not controlled by Li Tingzhi, and only obeyed Jia Nidao's orders, which restrained Li Tingzhi's rescue operation.

In order to break the encirclement of the Mongol army, Lü Wenhuan led his army to attack Wanshan Fort, the base of the Mongol naval army, but was defeated. Then Fan Wenhu led the naval army to reinforce Xiangyang, and the Mongolian army met the land and water armies, defeated the Song army, and Fan Wenhu fled alone. Later, Jia seemed to be a Taoist faction of Fan Wenhu, a big straw bag, to aid Xiang again, and the Mongolian general Ashu led the army to meet the attack, and the Song army was defeated again, losing more than 100 warships. After that, Jia Rudao organized several rescue operations, but they were all unsuccessful.

Just last year, the Mongol founders stepped up their attack on Xiangfan, and the Song reinforcements finally achieved a success. After Li Tingzhi moved to Yingzhou, he recruited more than 3,000 militiamen from Xiangyang Prefecture and Yingzhou, repaired and built a shipbuilding in the Qingni River in the northwest of Xiangyang, recruited militiamen, and used the Qingni River in the northwest of Xiangyang to fill 100 light boats with armor materials, and sent the chief Zhang Shun and Zhang Gui under the jurisdiction of the road branch to lead the rescue of Xiangyang. The second Zhang led the boat division to assemble the fleet in Gaotou Port, connected the ships into a phalanx, each ship was equipped with rockets and fireballs, and prepared strong bows and crossbows, Zhang Gui was in front, Zhang Shun was in the back, and broke into the encirclement of the Yuan army. When the flotilla reached the Mohong Beach, it was blocked by the Yuan ships that covered the river and could not pass. Zhang Gui led the army to attack, the soldiers were full of energy, first shot at the enemy ship with a strong crossbow, and then used a big axe to meet each other, broke through the blockade, the Yuan army was killed and drowned and countless people died, and then turned to fight more than 120 miles, arrived in Xiangyang on May 25, Zhang Shun died in the fierce battle, a few days later, the Xiangyang soldiers and civilians got his body in the water, wearing armor and holding a bow, angry eyes widened, the Xiangyang soldiers and civilians buried Zhang Shun with a deep feeling of admiration, and set up a temple to worship.

The success of this aid has greatly encouraged the military and people of Xiangfan. Although Zhang Gui's arrival brought hope to the defenders of Xiangyang, the situation was still very grim under the strict blockade of the Yuan army. After Zhang Gui entered Xiangzhou, he sent someone to sneak back to Yingzhou, contacted Fan Wenhu, the palace marshal of Yingzhou, and agreed to attack from the north and south to open up the peripheral communication lines of Xiangyang, and planned that Fan Wenhu would lead 5,000 elite soldiers to Longweizhou to respond, and Zhang Gui would lead the army and Fan Wenhu to join the division. However, Fan Wenhu retreated 30 miles two days before the meeting, and the Yuan army, after learning the news, quickly occupied Longweizhou and waited for work. The two armies of the Song and Yuan Dynasty launched an encounter in Longweizhou, the Song army suffered heavy casualties, Zhang Guili could not support, was captured by the Yuan army, and was killed unyieldingly, the Yuan army sent 4 Southern Song Dynasty soldiers to carry Zhang Gui's body to show Xiangyang City, forcing Lü Wenhuan to surrender, Lü Wenhuan killed the surrenderers, buried Zhang Gui and Zhang Shun together, and set up two temples to worship. Since then, Xiangyang and Fancheng have cut off contact with the outside world.

After losing contact with Xiangfan, Jia Rudao instructed Fan Wenhu to aid Xiang again, Fan Wenhu has been frightened by the Yuan army, unwilling to go, but did not dare to disobey Jia Rudao's order, so he only sent the palace to command Gao Hu to lead the army 5000, 300 warships, full of supplies and armor to the rescue, when the Gao Hu fleet went to the group of immortals, suddenly attacked by the Yuan army by land and water, unable to advance or retreat, in the Yuan army's "return artillery" and the attack of the naval warships to see that the whole army was going to be destroyed, Sun Hui five people suddenly appeared, Then there was an earth-shattering explosion on the shore, and the Yuan army, both water and land armies, was completely wiped out, and the Song army fleet was able to get out of trouble and successfully entered the city of Xiangyang. This is the second time that the Song Dynasty reinforcements have successfully aided Xiangfan since Erzhang came to aid, and once again gave great encouragement to the Xiangfan army and people.

After listening to Lu Wenhuan's story, Sun Hui already understood that the current battle of Xiangyang had reached the most critical juncture.

Fortunately for Sun Hui, the 10 "Huihui Cannons" were destroyed, so that the Yuan army could not use them to attack Fancheng - in the original history, the wall of Fancheng was bombarded by the huge stone projectiles fired at the "Huihui Cannon", and the Yuan army swarmed through the gap in the city wall and captured Fancheng. And Xiangfan is each other's horns, if Fancheng loses, Xiangyang is difficult to support alone, and failure is inevitable.

Speaking of the current situation, Lu Wenhuan couldn't help but be worried, especially worried about the powerful destructive power of the "Huihui Cannon", Sun Hui comforted him and said that the "Huihui Cannon" was not easy to make, and the Yuan army could not create a "Huihui Cannon" to attack Fancheng in the short term, even if the Yuan Army still had the "Huihui Cannon" and used it to attack Fancheng, he was an immortal and had a way to deal with it, so Lu Wenhuan was relieved.

At that moment, Lu Wenhuan asked Sun Hui what suggestions he had for defending the city, and Sun Hui thought that the top priority was to annihilate the Yuan army and restore contact with Fancheng.