On May 3, 1215, Bai Hui, the supreme commander of the Crescent River Valley Defense Area and the deputy commander of the Menglan Legion, finally couldn't hold back his anxiety and doubts, and began to send troops to the west to investigate. On the night of 4 May, a reconnaissance unit encountered Kuller's cavalry vanguard near Caoyi Valley. After some fighting, the reconnaissance force escaped and returned, and reported the information that the Chengtian cavalry had appeared near Caoyi Valley to Bai Hui.

"The army of the Chengtian Empire actually appeared near Caoyi Valley, could it be that the blood thunder of the previous few days was probably caused by Yaoguang. If it's broken, something must have happened. The more Bai Hui thought about it, the more frightened he became, as a tactically very conservative veteran, he should have sent troops in the direction of Caoyi Valley to search for him when the blood thunder appeared this year. However, because Sun Yaoguang's lightning attacks have always been purple and black, and Bai Shi once ordered him to stick to the Flying Fish Pass and not move lightly. Therefore, those blood thunders in the sky above Caoyi Valley did not attract Bai Hui's attention at first. But it was only later, when Bai Hui had not received news from the troops in the western direction, that the commander of the Crescent River Valley realized the seriousness of the problem.

The Crescent River Valley, located in the middle of Mörlan County, is a valley through which the wide, fast-flowing Crescent River irrigates the land. The entire Crescent River Valley area is 40 miles from east to west and more than 700 miles from north to south, with fertile land and rich products, which is the main grain producing area of the Beihai Kingdom. However, for this battle, the Beihai Kingdom implemented the strategy of clearing the wilderness early, not only organizing the people to plow the roads and destroying the roads, but also diverting the water of the Crescent River to turn the entire valley area into a flooded country, flooding thousands of households. What's even more unfavorable to the Chengtian troops is that the Crescent River Valley area is already swamped, and now it has been cleaned up by the Beihai Kingdom, making the entire Crescent River Valley area completely only cross by legs and boats. It's just that for the Shangdang Legion, it is simply impossible to cross the river by boat. Because, above the Crescent River Valley, a large number of troops of the North Sea Division cruised. If you hurriedly let the Chengtian soldiers who are not good at water start a water battle with the North Sea Division, it will be the rhythm of being wiped out in minutes. Moreover, the Beihai Kingdom built a pass called Jiansha Pass on the east bank of the Crescent River, three hundred miles upstream. This pass has been the operational base of the Crescent River Naval Army since the day it was built. Therefore, if you want to cross the Crescent River, you must go down to Tsim Sha Pass.

It's just that a huge problem is placed in front of Cha and Bu Hua and Su Butai. The reason why the Beihai Kingdom built Tsim Sha Pass is because Tsim Sha Pass controls the only sandy beach in the entire Crescent River that can be broken through by cavalry troops. This sandy land is ten miles wide and thirty miles deep. After the construction of Tsim Sha Pass, even if an enemy can break into the pass, it will be consumed by this huge depth in the pass. This is because in the entire Tsim Sha Pass, there are hidden passages arranged by the Beihai Army everywhere. In particular, the mechanism of wooden doors has been greatly applied here. Three thousand years ago, in the Battle of Montenegro, the Great Song Dynasty attacked the Beihai Kingdom in two ways. When the Song army won a series of battles in Montenegro County, the Great Song Emperor had a hot brain and sent all the Great Song sailors to cross the Yunhe River and transport millions of Song troops to attack Menglan County. The Beihai army stationed in Menglan County pretended to be invincible, and after successive defeats, they introduced the main force of the million-dollar elite Song army into Tsim Sha Pass. What shocked the world was that in the end, all the million-dollar elite divisions of the Song army mysteriously disappeared in Tsim Sha Pass, and none of them returned to the Great Song Dynasty. Due to this fiasco, the Great Song Dynasty gave up the plan to continue attacking the Beihai Kingdom after obtaining the Black Mountain County, but accepted it when it was good and concluded a peace treaty with the Beihai Kingdom.

Therefore, the generals of the Chengtian Empire were quite afraid of Tsim Sha Pass. Even if it is a fast platform with a lot of bad ideas, he can't think of any way for the time being. Then, if you can't outwit it, the Shangdang Legion can attack it. It's just that things are not as simple as they seem.

Because on the opposite bank of Tsim Sha Pass, there is also a very majestic pass, which is the world-famous Flying Fish Pass. The Flying Fish Pass was built by the Beihai Army on the basis of the Flying Fish Mountain on the west bank of the Crescent River. Flying Fish Mountain, the whole mountain is like a flying fish playing in the Crescent River, the mouth of the fish faces west, the tail of the fish faces east, it is the core military point of the Crescent River Valley. The Beihai army made perfect use of the geographical advantages of Feiyu Mountain and built the impregnable military fortress Feiyu Pass, which served as the gateway to the entire Crescent River Valley. However, why did the Beihai Kingdom build such a majestic pass in Feiyu Mountain? The reason is very simple, the section of the river between Feiyu Pass and Tsim Sha Pass is the shallowest part of the entire Crescent River, and the heavy cavalry troops of the Chengtian Empire can only pass through this section. Therefore, when the Beihai Kingdom turned the entire Crescent River Valley region into a vast ocean, this passage between Feiyu Pass and Tsim Sha Pass turned out to be the only choice for the Shangdang Legion. Because of this, the main force of the Menglan Legion will only be stationed in the Flying Fish Pass and Tsim Sha Pass. Except for the deployment of a corps of troops in Songshan, on the border with Beihai County, in the northernmost part of the Crescent River Valley, Bai Hui did not have to defend the rest of the place. And even if the Shangdang army took Songshan, their heavy cavalry troops would still not be able to pass, because Songshan was too high, thousands of zhang, and even the Beihai army stationed here was only guarding the foot of the mountain on the other side, because no one could climb over it except for the eagle.

On the morning of May 6, Chahe Buhua led the rest of the cavalry troops to join up with Kule's cavalry troops and approached Feiyu Pass. On the morning of the 7th, Subutai also led the main force of the Shangdang Army and all kinds of baggage, and the siege equipment hurried to the Feiyu Pass under the Crescent River Valley. The big battle was about to break out, and Bai Hui looked coldly at the Chengtian army that stretched for dozens of miles outside the pass, and his face was gloomy. He knew that the peripheral troops commanded by Sun Yaoguang were probably already unlucky.

"The situation is not good! Not to mention anything else, the Seventh Army is the elite of my Menglan Legion, and Yaoguang is the second best general in our army after Lord Shiraishi. Now that his life and death are unknown, it will be difficult for this Flying Fish Pass to be defended for a long time. Although our troops can retreat into the Tsim Sha Pass at any time, if we do not weaken the enemy's edge and retreat again and again, the morale of the army will inevitably fall to the bottom. Bai Hui pondered for a while and made a decision.

"Someone, send an order to all armies, immediately prepare for battle, and order the reserve troops to support at any time. In addition, the bed crossbow troops began to prepare, and the archer troops checked their respective equipment and immediately entered the Yukou Heights, waiting for the orders of their own commanders. In addition, tell the artillery division to prepare for the artillery attack within half an hour, and give the commander of the regiment a good greeting to those invaders outside the border in a while. ”