The letter for help was handed over to his herald. Taking advantage of the fact that these "barbarians" had not yet blocked the river, Hannibal had the herald and a few soldiers swim across the river to deliver the message to the castle upstream.

So far, Hannibal is still confident.

The barbarians outside the city will not attack the city at all. Even, these barbarians did not know about the burning of the surrounding rye fields.

The greatest manifestation of his self-confidence was that he did not even send soldiers, and at the beginning of the siege all the rye stored in the castle was ground into flour.

If you pay even the slightest attention, as a fortress engineer, the first lesson of defending the city is that "the attacking artillery fire can easily take advantage of the towering mill, so it is necessary to send enough soldiers on the first day of the siege to grind all the grain into flour before the mill is destroyed by artillery fire".

Defending a city is a science.

Science always needs experiments, but the test object of this science is the life of a soldier.

Hannibal was confident, both because of his knowledge and because his opponents were too weak.

Together, double the confidence, double the ease.

However, the day after sending out the letter for help, this confidence turned into a panic.

To Hannibal's amazement, the barbarians outside the city began to act.

He thought that these barbarians, with their courage and fear of death, would constantly storm the city walls and become the target for the soldiers defending the city to practice marksmanship.

Not really.

On the contrary, the barbarians outside the city very "professionally" began to dig trenches about three or four hundred paces from the bastion.

Through the telescope, Hannibal could see clearly.

Seventeen wagons laden with dirt lined up at intervals.

In groups of four, the first man hid behind the carriage, half-kneeling on the ground, digging a pit with a shovel.

The three men in the back kept piling up the excavated earth behind the side of the wagon, forming a breastwork that could withstand buckshot and ricochet.

When the first man had dug half a man deep, the four men worked together to push the covering wagon forward.

The first man continued to dig a half-man pit, and the three people behind separated the distance. The pit dug by the first person was enlarged and deepened, and the soil was piled up in front of the ditch.

Seventeen covered broken carriages and seventeen trench-digging squads formed a perfect arc around the fortress.

At this rate, it would take a maximum of three days for a trench to be dug as a starting point for the attack.

This...... It should not be the means of the barbarians.

"There's a Fortress Engineer on the other side, too." Hannibal came to a conclusion that he didn't want to believe the most.

If you want to be able to attack a city, you must first be able to defend it. If you want to defend a city, you must first be able to attack it.

The military science and technology of the Khitan officer on the opposite side are not outdated, and they are not like the information he collected - Dashun completed the military transformation at the level of the thirty-year war during the war eighty years ago, but has maintained this level since then, and has not improved.

This huge disparity, based on previous errors in judgment, turned Hannibal's extreme contempt from the beginning to panic.

He finally gave the first formal order to defend the city, and told the soldiers to go and grind all the rye into flour at once.

The artillery captain looked at the barbarians who were digging like marmots and asked Hannibal.

"Brigadier General, is it possible to attack them with artillery? Slow down their digging? ”

Hannibal held up the binoculars and looked at them for a while, rejecting the proposal of the artillery captain.

"The artillery of the defending side will inevitably be destroyed by the attacking side, which is a matter of time. As soon as the cannon is fired, the gun position will be exposed. ”

"If there are enough reinforcements. The artillery of the defending side should not hesitate to expose the gun position in advance to hinder the attacker's advance. Buy time for reinforcements to arrive, and time for the main army to fight. ”

"If there are not enough reinforcements. Defensive artillery, which is limited and inevitably destroyed, should be used at the most critical moments. Instead of early exposure, it was intensively destroyed by the artillery of the attacking side. ”

"How to choose, this requires a sober judgment on the part of the fortress commander."

He memorized the fortress course of the French military academy, which was the experience accumulated by France and Spain and the Netherlands for hundreds of years.

Exactly.

Pointing to the protective slope in front of the moat, Hannibal explained to the artillery captain, who did not know much about the defense of the fortress.

"The artillery is attached to the bastion, firing downwards, and as the enemy gets closer, the elevation angle of the muzzle needs to be constantly adjusted. Adjusting an elevation angle can take a long time, and the defender should try to avoid it. ”

"The protective slope in front of the trench is the best way to avoid this."

"The nine-degree angle extends to the protective slope in front of the trench, so that the artillery in the city does not need to adjust the elevation angle of the gun, as long as it has a fixed angle, it can block the long protective slope. The height of the ramparts, the angle of the protective slope, determined the optimal distance for shelling, which is a simple geometry. ”

"Artillery, it should be saved until the attacking side reaches the protective slope and starts attacking, and then fire. Aim to block the protective slope before the attacker's artillery destroys it, killing enough of the enemy. ”

This is one of the courses of the French military academy fortress.

Exactly.

Sin9 degrees, 0.15, the fort is three meters high, and the longest distance of this section of the protective slope is simply divided, about 20 meters.

The protective ramp allows the guns on the bastion to bounce and roll when they hit the ramp, and the killing range can be increased to 40 meters.

Behind the protective slope is the moat of the fortress.

At the end of the protective slope, there is a breastwork.

The defender's soldiers can stand on the breastwork and shoot at the slope, and cooperate with the artillery on the bastion and the musketeers on the high part of the bastion to form a three-dimensional crossfire in the upper, middle and lower layers.

Under the premise that the defender's artillery will inevitably be destroyed, the distance of about 40 meters on this section of the protective slope will be the place with the highest defensive killing efficiency.

It takes at least a day to two days for the attacker's artillery to counter and destroy after the fortress emplacements are exposed.

And for one to two days, the attacker will continue to attack. Because it is necessary to use the flesh of the infantry to test the artillery configuration of the defender and indicate the target of attack for the artillery.

When used properly, it can make the attacker bleed a lot.

However, if the protective slope is attacked, then the fall of the fortress is only a matter of time.

As long as you reach the protective slope, or use heavy artillery to counter the defending artillery and blast the city walls, or dig tunnels to bury gunpowder, you can attack the fortress after brutal hand-to-hand combat.

But now, his troops are not sufficient. Hannibal knew that the fortress might not last as long as he thought.

Once these marmots have dug in front of the protective slope, they can only send a limited number of troops to fight the opponent repeatedly. Abandoning the protective slopes and trenches, the fall of the bastion was a simple matter of time.

If you don't give up, it will also drain your own blood, after all, you only have more than a hundred soldiers in your hands, and your troops are seriously insufficient.

Hopefully, reinforcements will arrive before these men attack the protective slope.

Three days later, a trench three or four hundred meters in front of the fortress had been formed, and the speed of the excavation was visibly increasing every day, as the horse-drawn wagon cover team and the soldiers who were constantly familiar with the digging techniques were constantly being acquainted.

After the first trench was formed, Hannibal found that the men had been divided into two parts.

A part of the people, continuing to push the wagon for cover, dug a larger pit near the first trench.

The soil piled up slowly formed a small dirt bag.

Woven baskets were filled with earth, and walls were built in the place of small earthen bags, leaving a gun emplacement that was clearly intended for cannons.

You can't see the whole body of the person in the telescope, you can only see people rushing forward in the deep trenches, like a marmot on the grassland advancing in the tunnel.

Someone carried the wood and threw it into the "gun position", and it could be seen that someone inside was laying wood on the ground.

Hannibal frowned and counted the number of gun emplacements, which were about thirty.

That is, the attacking side had at least thirty heavy guns.

The reason why it was determined that it was heavy artillery was also a course in a military school:

For siege heavy artillery, it is necessary to lay wood, planks or logs under the gun emplacements to prevent the heavy artillery from sinking into the soil, resulting in the elevation angle of the muzzle cannot be mastered. The wood spread out like a floor reduces the pressure of the heavy artillery on the soil, and the pressure is divided by the area. Pressing on wheels and dirt is of course different from wheels pressing on the tiled floor.

That's still quite true.

Although there was no shadow of heavy artillery in sight, Hannibal, with his many years of experience in military schools, still deduced from those gun emplacements that the heavy artillery of the besieging side would soon arrive.

Except for those who dug heavy artillery emplacements, the rest began the classic Z-shaped trench extension.

The third lesson of the French military academy fortress engineering: the best choice for the siege party to approach the fortress is to start from the first trench, dig a Z-shaped trench, and approach with zigzags.

Dig a vertical line directly, and the artillery defending the city can shoot directly. If a cannonball falls into a trench, it will pierce a sugar gourd. It would be better to have no cover and hit the ground directly.

The turning angle of the Z-shaped trench should consider the shape of the fortress and the distribution of the star angle, calculate the best angle, and select the most labor-saving angle within an adjustable range.

The people who dug the Z-shaped trench were similar to the people who dug the first trench before.

It was also a group of four, the first one to dig deep in front and move forward, and the one behind followed to widen the trench.

For a few days, the perimeter of the fortress was like a spider's web.

Numerous trenches stretch inward from the first trench and twist and turn. The defenders could not see a single person exposed, only the dirt that kept flying out.

The terrifying silence on the battlefield doubled the pressure on the defenders in the city. Someone couldn't resist shooting at the trench, but to no avail.

The artillery captain also gave up the idea of tentative shelling, which had no effect on Z-shaped trenches, unless someone invented a shell that could explode, fired with a mortar with a very large curve.

On the eighth day of the siege, the Z-shaped trench had been extended to less than 200 meters in front of the fortress.

As Hannibal had expected, the Z-shaped trench was excavated at a distance of about 200 meters from the bastion and about 110 meters from the protective slope, and the excavation did not continue to advance.

Instead, it turned horizontally and began to dig a second trench parallel to the bastion.

Hannibal knew that the trench would be wider and deeper than the first. This will serve as a rally point for the final attack.

Another lesson in fortress engineering at the Institut de l'Institut de l'Institut de l'Informatique de l'Institut de l'Informatique de l'Institut

If possible, the fortress commander should send elite grenadiers. In the evening, when the digging was slack, the second trench was charged and the trench was filled.

Otherwise, once the second trench is dug and the attackers have a staging area and a forward position, the defenders' counterattack will be killed by the attackers' muskets.

That's still quite true.

But Hannibal couldn't use it.

Those damned Cossacks had all been buried outside the city before.

He didn't have any extra troops in his hands, and his simple defense was already stretched, and it was impossible for him to go out of the city to counterattack.

Through the telescope, Hannibal spotted that outside the first trench in the distance, many people were cutting down branches in the woods.

The branches were constantly being transported through the moats, and it was clear that the besieging party was preparing to fill in the moats.

Once the attack began, the daredevils would throw the twigs into the moats, fill in the trenches, and break down the last outer line of defense of the bastion.

In the second trench, the marmots continued to build new gun emplacements.

Once the assault begins, the long-range heavy artillery will suppress the defender's artillery - if the defending artillery counterattacks, the camera countermeasures will destroy it; If you don't fight back, let the lobes and mortars take the opportunity to enter the gun emplacements in the second trench.

Bombarding protective slopes at close range, forming random ricochets to kill and injure defenders hiding behind trenches.

Once the deployment is complete, it is time for the general offensive.

This is also the content of the military school curriculum.

Originally, according to the military academy curriculum, by this time, the commander of the fortress had already dug a tunnel in the fortress that extended outward.

Hang a bell on the top of the tunnel, and determine the location of the attacker who may dig the tunnel to bury explosives based on the direction of the bell. The fortress commander should send elite infantry, dig tunnels, and throw grenades to counterattack.

But this time, for the first time, Hannibal did not follow the curriculum of the military school.

Because of the dense artillery positions being built outside, he was very sober, and the besieging side did not need to dig tunnels, just bombardment with heavy artillery was enough.

Hannibal watched worriedly into the distance, and beyond the first trench, some men were maintaining a road that led to the forest in the distance.

It is clear that this road was prepared for the heavy artillery of the attacking side.

Winter is still far away, and the attackers have time. It can be seen that they are not in a hurry, but are waiting for the arrival of heavy artillery.

The front line was still hopelessly quiet, with only shovels flying and dirt flying.

There were no people, no guns, no cannons, but these flying dirt were more terrible than guns.

If you change someone else, you may laugh and disagree; But Hannibal as a fortress engineer, these scenes are like the Knights of the Apocalypse before the Last Judgment.

On the fifteenth day of the siege, the second ditch was basically formed. The newly built gun emplacements were still empty, but the reserved firing holes were clearly pointed, and they were the first fort where Hannibal was located.

That was the support point of the entire defense system, and obviously there was a detailed map of the fortress deployment on the opposite side, and it was easy to judge the key point of this inferior bastion.

Hannibal fell into deep despair.

Now the situation is already very clear, and the war with Russia is not as simple as I imagined. The Horde will not have heavy artillery, let alone understand this effective siege technique.

What's even more terrifying is that there is a big problem with the previous intelligence.

At least in terms of the attack and defense of the fortress, the Khitans in the south were not at the level of the Thirty Years' War.

A few days ago, he thought he was going to replicate the myth of the Portuguese in Cochin.

But now it seems that this may be his first and possibly last battle as a Stronghold Engineer.

Hannibal was ready to say his final prayers, knowing that it was only a matter of time before the fortress fell.

The only thing he could do was to use the only remaining artillery in his hand to bleed the attacker at the protective slope. The battle for the moat with the most tragic protective slope breastwork was delayed for at least twenty days.

By the time reinforcements from the upper reaches arrive, the fort can be held out longer, but it should be no later than before the first snow falls.

Just as he was in desperation, the soldiers in the city excitedly pointed to the lower reaches of the Heilongjiang River and shouted, like the desperate Israelites in the story who saw Moses parting the Red Sea.

"St. Andrew's Cross Flag!"

"St. Andrew's Cross Flag!"

"St. Andrew's Cross Flag!"

"O Holy Mother of Mercy!"

"Navy! Navy! It's our navy! ”