In mid-to-late April 1625, the same period when the Imperial Navy fleet was preparing and launching Operation Tsunami, the seasons did not change due to the war, the Far East melted the ice and snow, the vegetation revived, and the footsteps of spring came.

In this season of all things, the vast land on both sides of the Zhuolang River is particularly bleak. Since the beginning of spring, the Imperial Crusade Corps stationed in the Olevi Fortress have gradually freed themselves from the shackles of the bitter cold and launched more and more frequent military operations.

For five years before the 1625 Crusade, although the imperial authorities did not recognize the legitimacy of the new regime east of the Turbidity River, and the government of Koras did not recognize the vast territory of the Empire as the territory of the Yassanian Empire as the vast land west of the Turino Mountains, in fact both sides used the Turbidity River as a natural frontier and built strong fortifications along the river, and the railway bridge across the Turbid River was the only line of communication between the two fronts.

In February 1625, the authorities of the Assanian Empire mobilized a large army to launch an eastward crusade. The Far Eastern Frontier Army took the initiative to blow up the bridge on the Zhuolang River, and was forced to shrink its defenses to the depth of the Jiangdong area, using Lengxi Town as a base to establish a broader and more resilient defensive line.

During this period, the Eastern Expeditionary Corps under the command of General Engel was not in a hurry to cross the river and advance to the hinterland of the Far East in this cold season, but made steady progress, first sending the 1st Punishment Brigade (Palatina Brigade) and the 1st Breaking Brigade (Bazel Brigade) of the Eastern Expeditionary Corps to the defensive positions established by General Karl on the west bank of the Zhuolang River in the Olevi Fortress, to ensure a firm foothold in the strategic points along the river, and at the same time, these two troops will also be responsible for maintaining law and order in the vast countryside on the west bank and collecting as many military supplies as possible from the local population.

For more than 100 days, from February to April, the main forces of the empire did not cross the Turbidity River, which was of course due to frequent harassment by the militia and guerrillas in the Far East, and more importantly, because General Engel did not want to launch a large-scale offensive before the arrival of spring. Before the expedition, he had a heated argument with Field Marshal Sigmund about how much the climate and geography of the Far East had a negative impact on the marching operations, but he had to admit that the views of his former mentor were more realistic, and that it was not wise for his officers and men from the interior of the empire, most of whom lacked experience in high-latitude cold operations, to adapt to the extremely harsh winter climate of the Far East, and to brave the cold storm and snow to cross the river.

General Engel believed that "judging the hour and sizing up the situation" was the most basic quality of a military commander, and since he realized that his previous views were too bookish, it was not only foolish to insist on the wrong views in order to save face, but also irresponsible for the lives of his officers and men. Therefore, in the days he came to the Far East, he never put forward the argument of a quick victory that was often on his lips before the expedition, and what "four weeks" hit Colasburg, which is purely taken for granted in retrospect. The criticism of the government and the opposition for the slow progress of the Eastern Crusade and the call for an offensive to be launched as soon as possible were also laughed at by General Engel and ignored them.

During this long winter, General Engel and his Crusade Corps seemed to spend their days in fortresses and positions, doing nothing but killing time and wasting military rations, which attracted a lot of criticism at home. The reporters who had rushed to the front line with the army of the Eastern Crusade were also generally disappointed by the dreary atmosphere at the front, because there were no major battles worth writing about, and the trivial "law and order wars" such as the sweep of the guerrillas were not worth writing about repeatedly, and the newsletters sent back to the press were becoming increasingly boring and boring. In the end, the weekly long newsletter was simply cancelled and replaced with a short notice with the same content: "Everything is normal on the front this week, and there has been no major fighting", so that such a joke mocking the slow progress of the Crusade became popular in the social circles of the upper class of the Holy City of Assan:

"There was no fighting on the front lines this week, and it will be the same next week."

In fact, the Imperial populace in the rear did not understand the enormous pressure on the front-line officers and soldiers, and it was precisely the "Far Eastern security war" that the front-line reporters considered unworthy of reporting or could not effectively report due to press control, but on the contrary, the brutality of war was more evident than large-scale battles.

General Engel has in his hands such a disgraceful statistic. In the more than three months since the Eastern Crusade, although no large-scale offensive has been launched, the number of casualties among officers and men on the front line has been frighteningly large. In these more than 100 days and nights, the Eastern Expeditionary troops suffered a total of more than 1,000 attacks on this hostile land, except for a small number of small-scale assault battles organized by the regular army of the Far East, most of the attacks were guerrilla warfare launched by the local people and the westward militia, with only one main purpose: to kill and injure the living forces of the Eastern Expeditionary Corps by any means.

In Engel's view, the so-called partisans in the Far East were simply a bunch of crazy terrorists. Their way of fighting was contrary to chivalry, as long as they were able to kill and injure the enemy, they did not mind using assassination, sneak attack, or even feigning death and surrendering, which were despicable means despised by the imperial knights, and the "wind lance", the signature weapon commonly equipped by the Far Eastern guerrillas, complemented their despicable tactics, with a small gunshot, long range, great power, simple operation and continuous fire, and every time a string of evil bullets were fired from unexpected dark corners, so that the imperial officers and soldiers who went to the countryside to collect food or hunt down the guerrillas could not be guarded against it, and died of hatred. In just three months, the Imperial Crusade troops paid a huge price for maintaining law and order in the ruling area, more than 3,000 officers and soldiers died at the guns of the Far Eastern guerrillas, although most of the victims were servant infantry and mercenaries, but there were also knightly attendants and even regular knights belonging to the two elite knights of "Punishment" and "Breaking the Law", which made Engel regret.

It was during this period that the Imperial Navy Command proposed Operation "Tsunami" with the initial goal of seizing the Parnia Peninsula, and the Far East also ushered in the spring season, and the support from the Navy and the changing climate made General Engel realize that the opportunity he had been waiting for for a long time was ripe and that it was time to break through the Turbidity River moat. Before launching a general offensive, however, General Engel had to settle accounts with the Far Eastern guerrillas, who had harassed him for a whole winter and annoyed him, and completely wiped out the soil on which the guerrillas lived.

From the beginning of April, General Engel demanded that his officers and men maintain law and order on the west bank of the Turbid River by more forceful means, and entrusted the task of clearing the guerrillas to one of his most brutal generals, Major General Baron Bazel, commander of the 1st Brigade of the Knights of the Breaking Order.