Almost at the same time as Yang Guang, Gao Ying and others of the Eastern Route Army gathered in the Guangling Marshal Mansion to announce the strategy of crossing the river and attacking Chen, Yang Su, the marching marshal of the Western Route Army and the Qinghe Gong, who was part of the Sui Dynasty's three-way army of Chen, had already led the three armies of land and water, starting from Yong'an under the jurisdiction of Xinzhou, down the river, and rushing to the mouth of the Three Gorges Gorge to kill.

According to the marching strategy agreed with Yang Jian, the ancestor of Sui, when Marshal Chen returned to Chang'an to accept his appointment, the first task of the Western Route Army led by Yang Su was to go down the river from the upper reaches of the Great River, defeat the military forces deployed by Southern Chen in the upper reaches of the Great River one by one, realize the meeting with Yang Jun, the king of Qin of the Middle Route Army, and cooperate with the Eastern Route Army to pose a threat to the core area ruled by Nan Chen in the lower reaches of the Great River.

However, soon after Yang Su set off on a hundred-foot tall Wuya giant ship carrying 800 sailors, he encountered the first problem in his marching itinerary: the water of the Three Gorges was too turbulent and the water was densely covered with reefs, making it difficult for the Wuya giant ship to pass through the Three Gorges and reach the mouth of the gorge downstream.

Yang Su urgently convened his subordinates to discuss countermeasures, and for several days and nights they surveyed the water flow of the Three Gorges on the spot, and finally decided to take advantage of the short time when the water potential of the Three Gorges rose in the evening, and drove strictly according to the waterway route that had been surveyed many times.

However, a second problem followed, and then Yang Su was placed in front of him.

The Western Route Army marched to the vicinity of Liutoutan at the mouth of the Three Gorges Gorge, and a respout came to report that the Langwei Beach in the middle of the river in front seemed to be guarded by Nan Chen's heavy troops, blocking the waterway leading downstream.

Yang Su didn't take the Nanchen defenders guarding the Wolf Tail Beach to heart at first, so he ordered Liu Renen, the general and general of the Western Route Army, to lead 200 Yellow Dragon warships and launch a fierce attack on the Wolf Tail Beach. However, Liu Renen was defeated, losing almost half of the Yellow Dragon battleships.

Yang Su was shocked, and hurriedly ordered the troops to go to find out which Nan Chen general who led the army to guard the Wolf Tail Beach. As a result, the repulsion returned that the general of Nanchen on the Wolf Tail Beach was Qi Xin, the general of the naval army of the former Houliang, and although there were only a few thousand soldiers and horses under his command, they were all sailors who were good at water warfare.

After receiving the report, Yang Su led his generals to personally go to the river near the Wolf Tail Beach to investigate the battlefield situation, and unexpectedly found that Qi Xin not only personally led the army to defend the Wolf Tail Beach, but also built a fence on the north and south banks of the river near the Wolf Tail Beach to meet the defenders on the Wolf Tail Beach.

This unexpected discovery gave Yang Su the inspiration to defeat Qi Xin's defenders, he immediately gathered the generals in front of the army, and decided to divide the troops into three routes, promoting the strengths and avoiding the shortcomings, first attacking from both sides of the river with horse infantry at the same time, respectively breaking through Qi Xin's two fences on land, cutting off the supply lines of the defenders on the Wolf Tail Beach, and disturbing their military morale, and then led by himself 2,000 Yellow Dragon warships, with nearly ten times the enemy's military strength, to launch a frontal main attack on the Wolf Tail Beach, and strive to capture the Wolf Tail Beach in one fell swoop.

The first army sent by Yang Su, with the king of Kaifu as the general of the unified army, attacked the Nanchen army on the south bank of the river, and 500 pioneers rode horses to step on the enemy's camp, and it took less than half an hour to completely annihilate 1,000 Nanchen soldiers in the south bank of the fence and occupy the south bank of the fence.

At the same time, on the north bank of the river, Liu Renen, the general who was defeated by Qi Xin, returned to his familiar land, led two thousand cavalry troops to gallop to the Baisha fortress on the north bank of the river, and launched an unusually fierce offensive and defensive battle with the Nanchen defenders who were guarding the Baisha fortress.

When the Southern Chen general Zuo who stayed behind on the north bank heard that the Baisha fortress had been broken by the Sui army, he was so frightened that he sent someone to report to Qi Xin on the wolf tail beach in the center of the river, and on the other hand, he took the initiative to abandon the north bank of the other gate, dismissed the sergeants, and fled.

At dawn the next day, the two armies sent by Yang Su captured the other gates set up by the Nanchen army on the north and south banks of the river, completely cutting off the enemy's supply line on the Langwei Beach. At this time, Yang Su personally led as many as 2,000 Yellow Dragon warships and slaughtered the Wolf Tail Beach overwhelmingly.

Two thousand Yellow Dragon warships almost covered the entire river, and the defenders of Nanchen on the Wolf Tail Beach were spreading the news that the two southern and northern gates were broken by the Sui army overnight, and suddenly saw that so many enemy warships appeared on the river, and they had not started the war, and they had added a little timidity to their hearts, so Qi Xin personally took his knife into battle, and commanded the sergeants to intercept the enemy warships coming from the opposite side, but the army's heart was in turmoil, and most of the soldiers of Nanchen had no intention of fighting, and hurriedly shot an arrow at the Sui warship, and then rushed to retreat.

Yang Su rode a Yellow Dragon battleship, rushed to the forefront of the Sui Dynasty's naval fleet, and as soon as the battleship broke through the enemy's defense line and approached the shore, he took the lead, jumped down from the battleship, waved his sword, and fought with the defenders of Nanchen on the Wolf's Tail Beach.

Qi Xin saw that there were more and more Sui troops rushing to the Wolf's Tail Beach, and he had the potential to annihilate the defenders on the beach, so in desperation, he had to hurriedly board a clipper boat under the protection of several personal soldiers, and Zhang Fan went down the river and fled to Qiting downstream.

Yang Su led the Sui army on the western route to capture the Langwei Beach by means of joint water and land operations, annihilating nearly 5,000 defenders of Nanchen, and then ordered scouts to spread the news widely along the river, claiming that the Nanchen naval army was simply not vulnerable to a blow from the Great Sui naval army, and Yang Su, the prince of Qinghe, led dozens of Wuya giant ships down the river to completely wipe out the Nanchen naval army deployed along the river.

Although Qi Xin, who fled to Qiting alone, repeatedly explained to Nan Chen's guard general stationed in Qiting, Nankang Neishi Lu Zhongsu, that the defeat of Langweitan was not defeated by the Sui Dynasty's naval army, but still the Sui Dynasty's powerful army played a decisive role, but Lu Zhongsu did not listen to Qi Xin's words at all.

Intimidated by the Sui army's claim that there were dozens of five-tooth giant ships, Lu Zhongsu knew that the hundreds of Qinglong warships under his command could not match them at all, so he did not discuss with Qi Xin, so he followed the stupid method of the Eastern Wu naval army to deal with the Western Jin Dynasty general Yanghu three hundred years ago, and pulled up three iron chains across the river on the north bank of the river near Qiting, intending to intercept the Sui army's five-tooth giant ships.

After Yang Su heard the report, he immediately ordered the 1,000 Qiang people recruited in Xinzhou to cross the mountains from the north bank and take the lead in carrying out a surprise attack on Qiting. He took advantage of the fact that Lu Zhongsu and Qi Xin were busy parrying the surprise attack of the sharp soldiers, and ordered the sergeants to pull out the three iron chains across the river, and with the four five-tooth giant ships as the vanguard, they broke through the blockade of the Nanchen defenders on the river, and sailed straight to Qiting, the gateway to the middle reaches of the river.