Because of the artillery battle between the two sides, there seemed to be no one on the wall of the city, but there were many sentries behind the battlement wall, and they all saw the 10,000 Ming troops passing through the city from behind the battlements, and immediately rushed down to the city to report to Yixin and Colonel Karsakov.

"At least 15,000 Ming troops have entered Russian territory...... It seems that the Ming army has received the news of the declaration of war! ”

Colonel Karsakov quickly made a judgment, and he guessed that this time it was likely that the Ming army took the initiative to declare war! The Tsar probably didn't even know what to do.

"Order the soldiers in the military camp in the north of the city to retreat into the trading city!"

Colonel Karsakov hurriedly ordered the company outside the city to retreat, he did not want to lose a company of troops in vain.

"Mr. Colonel, do you just let Ming Gouzi besiege the city?" Yi Xin was also in Karsakov's headquarters, and he asked a little unwillingly.

"Let them surround it, buy and sell enough food in the city for us to eat for a year, and we are not afraid of surrounding!"

Yi Xin sighed, these grains are the rations of hundreds of thousands of banner people, women and children! Although Muravyov promised that he had prepared enough rations in the towns and villages along the way to Western Siberia to ensure that all of them would not go hungry on the way, how true was this statement?

"Mr. Colonel, Ming Dog won't just surround and not fight, right?" Yi Xin asked with some trepidation.

"For the time being, I think the artillery battle just now should have made them know how powerful the fortress of the Dao Trading City is." Colonel Karsakov was somewhat smug.

If the Ming army had a little bit of Western military common sense, they would definitely not storm a strong fortress, because such a castle could not be solved by corpses and bloodshed at all! The correct thing to do is to build parallel trenches and communication trenches around the fortress. If viewed from the air. It's like a spider's web. Wait until the completion of the works on the parallel trench and the traffic trench. The real shelling will begin, and the enemy's infantry will gradually shrink the encirclement under the cover of artillery......"

In the city defense headquarters in the city, Colonel Karsakov calmly introduced Yixin to the most commonly used fortress attack technique in the West. He said: "This tactic, called the parallel trench attack method, was invented by Marshal Vauban of France one hundred and seventy or eighty years ago. And the buying and selling city that we are defending now is a Vauban Type 1 bastion, which is also the design masterpiece of this Vauban marshal. ”

"Mr. Colonel, can we hold it then?" Yi Xin directly asked him about the question he was most concerned about, he was not interested in listening to Colonel Karsakov talk about what a Vauban Type 1 fortress was and how to capture it.

"Your Majesty the Great Khan. Rest assured! The city of buying and selling is extremely strong, and it will be able to hold it. Colonel Karsakov still had no expression on his face, only the constant tapping of his fingers on the map table revealed his inner anxiety.

He was personally responsible for supervising the construction of the fortress of the buying and selling city, and it was indeed a fortress that was difficult to conquer. But it's not impossible to capture! If he is allowed to command the 60,000 new army equipped with a large number of artillery, it will take up to 4 months, and the city will definitely be breached by himself!

As Colonel Karsakov had expected, the Ming army did not have the idea of taking their lives to buy and sell forts, because they knew that it would not work.

Luo Junqi's staff officers and staff are all top students of the Royal Army Military Academy, and they are formulated for this gangster-turned-Ming army general. By combining the construction of parallel trenches and fire attacks, the main position of the defenders of the city was pressed step by step, and the encirclement tactics were gradually narrowed. The ultimate goal was to put the entire city within the effective range of the superior artillery of the Ming army.

It's interesting to say. This siege method of long trench siege and artillery bombardment has a similar name to the Vauban Type 1 fortress, called the "Vauban Attack Method". Like the design of the Vauban-1 bastion, it is the work of Marshal Vauban, the great French military engineer of the 17th and early 18th centuries. Many of his writings in "On the Attack and Defense of Fortresses", "Essays on the Construction of Cities", and "On the Siege of Cities" were still regarded as classics by the military academies of various powers until the middle of the 19th century. The Royal Army Military Academy of the Ming Dynasty also taught the officers of the Ming Army the methods of siege, defense and fortification invented by Vauban to the officers of the Ming Army.

However, in addition to the "Vauban Attack Method", the Ming army also had another siege weapon - starch explosives.

At the same time that the Ming army began to dig trenches and besiege the city, a team of horse-drawn wagons were pulling ammunition from Tengger City, 600 miles away, to the artillery positions outside the city, some of which were Hochsky grenades, filled with the nitrate H starch invented by Emperor Zhu - this is also the most powerful explosive in the world at present! The production process is also relatively simple, only need to use concentrated nitric acid, concentrated sulfuric acid, high-quality starch at 30~40 degrees Celsius after stirring to obtain crude nitrate H starch, and then use soda ash and concentrated ammonia water to neutralize and remove the residual acid in the crude nitrate H starch can obtain nitrate H starch that can be used for artillery shell charge.

Of course, this relatively simple process was simply not possible in the Chinese handicraft industry five or six years ago. Even now, only Jason's pharmaceutical company and Lan Fangxing's arsenal have the capacity to mass-produce nitrate starch, as well as the raw materials such as nitric acid, sulfuric acid, starch, soda ash and ammonia (not ammonia, of course) needed to produce nitrate starch. Moreover, the vast majority of the engineers working in China are still hired from Europe with high salaries. In fact, there is no golden finger or shortcut to the country's industrialization road, and it can only be improved slowly and down-to-earth.

With so many foreign engineers working at Jason and Lan Fang, it is unlikely that a powerful explosive such as nitro-H starch – an invention that has been patented in the world's major industrial countries, including Russia, is no longer a secret weapon. Therefore, the Russian arsenal has also begun to produce nitrate H starch for the production of bombs! However, the Russian army in Eastern Siberia and the Eight Banners Army in the city did not have such advanced weapons. Now the nitrate H starch in the hands of the tsar is limited, and of course it will be used in the more important Western Front.

……

"This is the defense map of the buying and selling city?"

On August 8, in Chengde Summer Resort, Zhu Jishi looked at a map of the fortress in front of him that seemed to be snowflakes, and asked with a frown.

"Your Majesty, this is not a city defense map of the buying and selling city, but a standard Vauban Type 1 fortress map." Liu Jiong, chief of the general staff, was born in a professional class and went to the Sanchester Military Academy, so he knows what is going on with the Dao Fortress, "This is a trench, usually a few zhang to a dozen zhang wide, and the inside of the trench is an inclined embankment...... It's a steep slope with a lot of angles, and it's hard to climb. When the troops climbed the inclined embankment, they would be subjected to crossfire from prismatic and triangular fortresses such as triangular forts, hollow forts, and solid forts, and there were almost no dead spots to dodge! ”

What a cruelty! Emperor Zhu also knew that a well-built fortress was difficult to capture!

Zhu Jishi said lightly: "Hmm, let Luo Junqi not worry, fight slowly, and be ready to spend the winter under the trading city." Historically, the Qing Tartar puppet emperor Kangxi took 10 months to besiege a Yaksa city before it was successful, and today's trading city fortress is not known to be much stronger than Yaksa City, even if it takes 10 months to fight down, it is not ashamed. ”

Liu Jiong said in his heart, the Son of Heaven is really a soldier, and the most taboo thing about attacking the fortress is impatience. Luo Junqi is not a siege master like Vauban either, and he has not studied fortresses and military engineering before, so if he wants him to break the city in a short period of time, he is afraid that he will have to fill it with a mountain of corpses and a sea of blood.

"But please rest assured, the design of this Vauban Type 1 fortress is one hundred and seventy or eighty years ago, and there were no starch explosives and A oil explosives at that time."

Liu Jiong smiled and said the good news: "The staff officers of the General Staff Department have found a way to conquer the fortress of the trading city. In fact, it is very simple, that is, use the parallel trench attack method (Vauban attack method) to dig the trench to a place 500 yards away from the fortress of the trading city, and then set the 12-pounder howitzer and the 24-pounder howitzer in the trench, which is the attack dead angle of the cannon mounted on the trading city, and their howitzers do not have high-power flowering shells, so there is no threat to our howitzers. Therefore, we can use howitzers to fire flowering shells at the fortifications of the trading city, or we can shoot flowering shells directly into the city. (To be continued......)