Fearing being killed for his overwhelming merits, the empress decided to marry him.

“Your Majesty, these watchtowers are the new fortifications I have set up for the border defenses.”

"Look, each watchtower is constructed using a combination of earth and wood, and each stronghold can accommodate anywhere from a dozen to a hundred people for defense at the same time."

They firmly secured the long border with a triangular structure, with three points forming a defensive triangle that could block enemy attacks from multiple directions.

Most importantly, the construction cost is extremely low; the cost of constructing the outer wall of a watchtower is only a fraction of the cost.

The minimum cost is only a few dozen taels of silver, and even a fortified tower with several hundred people only costs a few hundred taels of silver.

This is far more economical than expanding border outposts that often cost tens or hundreds of thousands of taels of silver, and it also saves the imperial court a great deal of unnecessary expenditure.

Lu Lin looked around and suddenly asked, "Then may I ask, Commander Shen, if the enemy attacks with heavy siege equipment, how will these simple earthen and wooden structures withstand it?"

Upon hearing this, Jiang Mengxuan also gave Shen Lang a questioning look.

Unexpectedly, Shen Lang replied very decisively: "If we encounter heavy siege equipment, we should abandon this stronghold and the guards in the blockhouse should retreat to the next stronghold to continue holding it."

"Then what's the point of these watchtowers and strongholds?" Lu Linqi asked. "If these strongholds can be easily breached, isn't it just a waste of manpower and resources?"

These words were endorsed by many knowledgeable military officers present.

Indeed, these watchtowers are too rudimentary; what is the point of setting them up?

Unexpectedly, Shen Lang laughed: "Minister Lü, do you really think these watchtower structures are meaningless?"

Lu Lin cupped his hands in greeting and replied, "I hope that Commander Shen can enlighten me."

Shen Lang said, "Very well, before I explain, please have Minister Lü answer one question for me first."

If the Northern Yan army invades the northern border, and the Bingzhou army is desperately short of food and supplies, what should Minister Lü do in this situation?

Without hesitation, Lü Lin replied directly, "Naturally, we will mobilize troops and supplies from the capital and send them north along the river to provide assistance."

"Then may I ask Minister Lü, how much manpower and resources would be required to transport 50,000 troops northward at once?"

"At least 600,000 shi of military rations, 300,000 civilian laborers, and more than 10,000 mules and horses, and we will have to see if we can increase them depending on the actual situation!"

As the Minister of War, he certainly possessed such calculation abilities, after all, he had been in charge of the allocation of food and supplies in the border areas for many years and was very familiar with it.

Shen Lang nodded: "Then the question arises: how do we anticipate the most realistic circumstances at present?"

After all these manpower, material resources, and even animal power were transported to the border, they repelled the Northern Yan invasion.

From a cost perspective, did my Chu army win or lose?

Upon hearing this, Lü Lin fell silent.

He hadn't considered this issue from this novel perspective yet.

Ye Mo, however, became somewhat interested in the question raised by Shen Lang.

Jiang Mengxuan watched Shen Lang quietly, eager to know what he was trying to say.

Seeing that Lü Lin did not answer for a long time, Shen Lang said directly: "No need to consider it. Whether it's a small victory or a big one, the cost of defense is more than ten times that of offense."

Unless you can extract sufficient benefits from the war, this mode of warfare...

This will only drag the entire State of Chu into an inescapable economic quagmire.

"Ugh--"

Lü Lin actually knew this principle, but he was too ashamed to say it aloud, so he could only sigh helplessly.

The other two who understood the reasoning were Ye Mo and Lin Yu.

In fact, they discovered this unsolvable problem even earlier than Shen Lang, but they just didn't dare to say it out loud.

Because raising this issue would inevitably invite criticism from officials, ruining one's reputation.

But Shen Lang brazenly and openly brought up this most pressing issue right in front of everyone.

After all, one of those officials who dared to criticize him today was imprisoned, and another was sent to the Imperial Hospital for emergency treatment after being scolded by him.

Who would dare to make trouble for him?

Shen Lang continued, "Winning a defensive battle without gaining any war dividends is destined to be a losing proposition."

While the success in repelling foreign invasion is certainly commendable, from a practical standpoint, it is not suitable as a long-term military strategy.

Even assuming we don't need to allocate troops and supplies from the central government, simply being able to defend against foreign invasion would still be a losing proposition.

After all, the imperial court invests a significant amount of money in the border regions every year to fortify the defenses of the fortresses, which is a considerable expense in itself.

These heavily fortified fortresses and strongholds are crucial to the stability of the Chu state.

Once the fortress is breached, the settled people living within the vast territory of the Great Wall will become lambs to the slaughter, utterly defenseless.

To be honest, the investment and return are completely disproportionate.

Ye Mo couldn't help but interject, "So these rudimentary civil engineering works can solve this problem?"

Shen Lang: "While it cannot completely solve this problem, it can save a lot of financial expenditure and achieve considerable results."

Jiang Mengxuan: "Tell me in detail."

Shen Lang pointed to the map and said, "The border issue of Chu that I just mentioned involves the cost of war."

A fortress, built at a cost of hundreds of millions of taels of silver, was used to defend against a poorly equipped cavalry force that relied on horses for mobility.

The cost is extremely asymmetrical, but what if it were replaced with a small watchtower made of earth and wood?

The destruction of a stronghold would at most result in a loss of a few hundred taels of silver, but the enemy would have to muster ten or even dozens of times more troops and siege equipment.

Putting aside other factors, the daily food consumption alone is astronomical, and the advance of an army carrying siege equipment would inevitably be slow.

Once one stronghold is captured, another awaits. How long can they sustain such an offensive?

If they withdraw, we can immediately launch a counterattack, rebuild a fortified position, and even use it as a base to continue our advance.

This significantly reduces our combat costs, while the enemy must pay dozens or even hundreds of times more to capture a single pillbox.

So, which side actually benefits?

After listening to Shen Lang's analysis, Jiang Mengxuan's eyes lit up.

She's a genius; the husband she chose is truly a genius.

How did he come up with the idea of ​​making such a perfect use of such a simple earthen and wooden structure?

Lu Lin and the others immediately understood the key point and showed Shen Lang a look of heartfelt admiration.

Ye Mo even wrote down everything Shen Lang had just said in his notebook and carefully studied it.

The more he looked at it, the more he felt that this type of advancing watchtower was simply an unsolvable problem.

Moreover, with the concept of cost in mind, Ye Mo calculated that each watchtower cost 500 taels of silver, so a thousand watchtowers would cost 500,000 taels, which is dozens of times lower than the annual investment in border fortresses.

"Furthermore, the earthwork strongholds must be built along the river, so that while soldiers are guarding the fortified towers, they can also find opportunities to launch attacks on isolated enemy forces nearby."

If we successfully conquer this region, it will belong to our Great Chu territory. If the enemy proves too formidable, we can retreat to our fortified towers and await reinforcements.

The officials fell silent once again.

Because they simply couldn't figure out how to counter this utterly shameless tactic.

In fact, Shen Lang's blockhouse advance tactic was based on the "Great Wall compression tactic" used by Tsarist Russia to expand from the east and west.

By occupying major river channels and constructing several watchtowers in suitable areas, a force could pose a significant threat to external forces within a radius of hundreds of kilometers.

The various khanates established by nomadic peoples in Inner Asia were eliminated by Tsarist Russia through this method of gradual encroachment along rivers.

Finally, they expanded eastward to the Outer Northeast region, completely shrinking the living space of nomadic peoples in the late 19th century.

If you're not interested in the history of Tsarist Russia's expansion, there's a classic war that can illustrate just how terrifying civil engineering can be.

That was the Battle of Jinchuan, the most valuable of the Ten Great Martial Arts of the Horse Demon Lord Gai Zhanglong.

The battles of Greater and Lesser Jinchuan lasted for eight years.

The second war, in particular, lasted a full five years and cost the Ma Yao 600,000 men and 70 million taels of silver, with over 10,000 deaths, before it was finally won.

The reason why the battle was so difficult was that the Greater and Lesser Jinchuan occupied strategic locations and built watchtowers and fortresses, which were densely distributed throughout the Jinchuan region, seriously hindering the Qing army's advance and concentration of forces.

Relying on the terrain and fortified watchtowers, the chieftain, with only tens of thousands of people, managed to withstand multiple attacks from the Eight Banners of the Ma clan. Gai Zhanglong's victory was entirely due to the national strength of hundreds of millions of people, who single-handedly supported him to win.

This clearly demonstrates that civil engineering was an extremely unscrupulous practice before the maturity of firearms, and it would be a waste not to promote it now.

In addition, at the end of the 17th century, the Tatars' last westward expedition was also repelled by the numerous manor fortresses scattered throughout Europe.

After this battle, nomadic groups were completely weakened, and Europe was finally freed from the nightmare of slavery by nomadic groups.

This provided a relatively stable environment for the Western Renaissance, which truly allowed the West to embark on a path that surpassed Chinese civilization.

Jiang Mengxuan: "Today is the day of our royal army's triumphant return. These plans can be discussed another day. It is approaching noon now, so I should hold a banquet to welcome the three armies and wash away the dust of their journey."

"My lords, follow me to Jianye Palace and cheer for my royal army!"

"May the Great Chu last ten thousand years! Long live His Majesty!"

Amidst the cheers and shouts of the officials, Jiang Mengxuan confidently walked out of the Taiji Hall.

As she passed by Shen Lang, she couldn't help but give him a slight smile.

Since meeting Shen Lang, she realized that the throne wasn't so difficult to sit on after all; there was nothing he couldn't handle.