The four princes were very worried about exposing the problems regarding Luzon.

However, little did they know that this problem no longer existed.

"These little bastards are really getting bolder and bolder. When they left the capital before, their true natures were exposed. Now that they have fled to Japan, they are even more unscrupulous."

"And there's this guy Lao Si. I thought he was the one who listened to me the most, but it turns out he's the one who hid the most. This Sihai Chamber of Commerce is probably the one behind Lao Si."

In the Huagai Hall, Zhu Yuanzhang cursed as he looked at the intelligence in his hand.

He always thought that apart from the eldest son, the fourth son was the most obedient among his sons, but now his true colors have finally been revealed.

Zhu Ying heard this, but did not respond to the old man's words. Instead, he said, "I didn't expect that the matchlock guns would spread so quickly. Even the Sulu Sultanate has so many matchlock guns."

The four princes thought that the imperial court was unaware of their sending troops to Luzon, so they used their connections to blockade the sea area.

But they forgot one very important thing, that is Zhu Ying's Imperial Military Academy.

Even Zhu Di, who had seen similar training at the grassland military base, could not have imagined that it would have such a great impact.

Most of the students who graduated from the Ming Military Academy went to David's institute.

With professional training, even if Zhu Ying copied some methods from later generations, they are not comparable to today's era. After all, there is a difference in times.

Therefore, after these students who graduate from military academies enter the army, it is easy for them to excel in all aspects.

In Japan, almost all of the new generation of middle-level military officers have more or less connection with the Ming Military Academy.

Even if they are not direct graduates, they have received training from graduates.

Ideological education has always been something that Zhu Ying cares about particularly, and this trend started from the bottom of the military.

Standing at the height of a vassal king, it is naturally difficult to feel it.

But it is undeniable that among the middle-level officers sent to Luzon by the four feudal lords, more than 70% remain loyal to Zhu Ying.

Especially here in Zhu Gang.

Zhu Gang relied on the Qunying Chamber of Commerce to gain a foothold in Japan in the early days, and infiltration was Zhu Ying's forte.

When Zhu Gang sent the first batch of troops to Luzon, Zhu Ying received the news almost at the same time, including the discovery of the gold mine.

It has to be admitted that even if Zhu Ying knew there were gold mines in Luzon, it would be difficult for him to take action.

After all, Ming Dynasty is a country of etiquette, so how could it send troops directly to Luzon to rob? Mining itself is a difficult problem, which requires a large number of manpower. It is obviously not cost-effective to recruit people from Ming Dynasty.

Moreover, this place is very far away, and probably not many people are willing to go there.

The plan of the four princes was exactly what they wanted.

The early capital accumulation will eventually involve bloodshed. Letting the four princes do this will not affect the reputation of the Ming Dynasty. What a good thing.

Naturally, I just let it go.

After all, Ming Dynasty's current trade volume is extremely large, and no matter how much money the four princes have, it can only flow into Ming Dynasty's market.

Looking at the entire Asian region, there is no market comparable to that of the Ming Dynasty. Even the prosperity of maritime trade in Southeast Asia today is because the Ming Dynasty opened up the sea.

However, while maritime trade is booming, there are both advantages and disadvantages.

For example, the matchlock gun.

The matchlock gun itself showed signs of spreading, which was discovered when Zhu Ying arrived in Champa last year.

Firearms such as muskets had already spread throughout the world as the Yuan Dynasty, or the Mongol Empire, developed.

Even in the early Ming Dynasty, when Zhu Yuanzhang focused on firearms, other countries were not much behind.

In the confrontation with Annan, Annan's firearms showed that they were not inferior to those of the Ming Dynasty in many aspects.

If it weren't for Zhu Ying's existence and his expertise in the manufacture and improvement of firearms, the Ming Dynasty's firearms might still be at a disadvantage in Annan.

Historically, when Zhu Di sent troops to attack Annan, he did not gain an advantage in firearms.

Even the Shenjiying that was developed later could only be considered a local armed force, and there was no way it could compare to the current prosperity of firearms in the Ming Dynasty.

In the present-day Ming Dynasty, branches of the Gunpowder Bureau have already established firearms factories in every province and are vigorously producing firearms.

However, this also made it easier for secrets to be leaked, and the method of building the matchlock gun was soon learned by other countries.

The main thing is that the matchlock gun itself does not have any design barriers.

Almost 40% of the Ming Dynasty’s army is currently equipped with matchlock guns. By simply disassembling them, we can understand the structure of the matchlock gun and replicate it.

The granulation of gunpowder is no big secret.

Under the inducement of huge sums of money, some craftsmen will eventually become traitors.

The Ming Dynasty’s pie was so big that it was impossible to cover everything.

But for now, in terms of quantity and quality, the Ming army is naturally the best equipped.

"Big Sun has been visiting the Research Department a lot recently, trying to develop a steam-powered ironclad ship, and now he's making some progress."

Zhu Yuanzhang actually did not have much interest in those small countries, even though gold mines had been discovered in Luzon.

The Ming Dynasty's treasury is no longer short of money. After deducting all expenses, the treasury still has millions of dollars in revenue every month. Zhu Yuanzhang no longer has as much interest in money as he once did.

I was particularly curious about the steam-powered ironclad ship described by my eldest grandson, which could sail without the help of wind.

Upon hearing this, Zhu Ying said helplessly: "It's stuck now. I don't know how long it will take to make it."

Zhu Yuanzhang asked: "What is the problem? We have so many talented people in the Ming Dynasty now. We can solve it by pooling our wisdom."

Zhu Ying said helplessly: "It's not a human problem, it's a material problem. For heat preservation, insulation, and sealing, even if it is made of gold, the effect is very poor. Even if it is made, there is too much coal needed for navigation, and it is not very meaningful."

Zhu Yuanzhang thought for a while and said, "If gold doesn't work, then let's try something else. Our Ming Dynasty is vast and rich in resources. How can we be stumped by this? Even if our Ming Dynasty doesn't have it, we can look for it overseas."

"Didn't Li Jinglong go to the West? Send a fleet to catch up with him and ask him to find what our eldest grandson needs."

Zhu Ying was silent for a moment.

If you want to solve the sealing problem, the most important thing is rubber. The role of rubber is irreplaceable, and currently this thing is not available even in the West.

The natural rubber tree seems to be native to South America.

It is extremely difficult to find it at such a long distance.

Zhu Yuanzhang seemed to see through Zhu Ying's thoughts and said, "We now have two million soldiers in the Ming Dynasty. Except for a few small countries, who can resist us? Some small countries may have thousands or tens of thousands of people, and we can easily destroy them."

"Grandson, don't worry too much. It doesn't matter if it takes a long time. At most, we can just send more expeditionary forces out."

"As long as this thing exists, it will definitely be found."

Zhu Yuanzhang's words were deafening.

Yes.

Since I know the place, why can't I send someone to look for it?

Is it because it's too far away?

There is the vast Pacific Ocean between the Ming Dynasty and South America.

With today's navigation methods, crossing the vast oceans to reach South America is an arduous task that would be beyond description.

There are currently two feasible methods.

One is to travel by land, from northeastern Asia through the Bering Strait to North America, and then go all the way south to South America to look for rubber trees.

The second is to send an ocean-going fleet, advance along Li Jinglong's current direction, arrive in Europe, and then depart from the coast of Spain in Europe, imitate Columbus to cross the Atlantic Ocean and head to South America.

After all, the discovery of the American continent began here.

In terms of safety, it is actually safest to go to North America via the Bering Strait and then to South America.

Because the American continent has not yet formed a strong concept of a nation and is still in the stage of tribal civilization.

Even if it is just an expeditionary force of 10,000 people, they can push forward all the way.

The only downside is that it takes a long time.

Taking Columbus's route would take a slightly shorter time, after all, in most cases you would be traveling by ship, so the speed would naturally be faster, but the risks at sea are incalculable.

Since both paths are feasible, how should we choose?

As the grandson of the Ming Dynasty, Zhu Ying said, "I want both the bear's paw and the fish."

Whether it is by land or sea, with the current capabilities of the Ming Dynasty, it can naturally take either route.

At this moment, a person suddenly popped up in Zhu Ying's mind.

Zhao Yuanhong.

Zhao Xiucai, whom Zhu Ying once admired very much, was sent to Annan as a military advisor for state affairs.

The last letter I received said that he had become the Grand Chancellor and Minister of Finance in Constantinople, Europe.

This is a huge help.

"It seems that your eldest grandson has found his direction?" Zhu Yuanzhang asked when he saw his eldest grandson in deep thought.

Zhu Ying hesitated for a moment and then replied, "When I was in the Western Regions, I once heard of a tree called the Weeping Tree. When you cut its bark, a milky white sap will flow out. This sap is inedible and is highly poisonous."

“But after solidification, it becomes extremely closed and can recover from impact.”

"If we can find this tree, then the problem of steam ironclad ships can be solved."

After a slight pause, Zhu Ying added: "I heard it from a wandering old man. I don't know if it's true or not. He said that the tree was planted and grew in a very hot place. It feels more like a legend."

Zhu Yuanzhang thought for a while and asked, "Did he tell me where he had seen this tree?"

Zhu Ying nodded: "It is said that in the far east, there is a brand new continent. If you walk straight from the northeast of Daming, through the four seasons of snow, across several islands, you will reach the vast continent."

"Further south, there are forests with trees several meters tall and dangerous rivers. They are still in the ancient tribal era, full of barbarism, and there are even indigenous people who eat humans."

Zhu Yuanzhang frowned slightly when he heard this, and he looked like he was recalling something.

After a while, he hesitated and said, "Perhaps, the place that the old man that my grandson met talked about does exist."

Zhu Ying was stunned and didn't react.

The old man is of course fake, but the American continent is real, but why does the old man say that?

Zhu Yuanzhang explained: "I like to read books, whether it is official history or unofficial history."

Zhu Ying nodded slightly. He knew that even when he was busy, Zhu Yuanzhang would always set aside some time every day to read.

Take the Huagai Hall now for example, the walls are full of books.

Zhu Yuanzhang had read most of these books, and even if he had not, he would read them in the future.

It is easy to say that you never stop learning, but Zhu Yuanzhang truly did it.

Zhu Yuanzhang continued: "In the folk history, there are records about Qin Shihuang's search for elixirs overseas."

"The most famous of them is naturally Xu Fu."

"However, what kind of person is Qin Shi Huang? How could he place all his hopes on Xu Fu? In addition to Xu Fu, there are naturally more people sent out to seek immortals and seek immortality."

"The Qin Dynasty fell after 15 years, but at the beginning of the Western Han Dynasty, there was a record that dozens of people returned. They were old Qin people. They said they went to the far east and returned after decades."

"They said they went to the place where the Dongshan Sutra was located and saw armadillos that only existed in ancient books, as well as many strange beasts."

"This incident is only recorded in unofficial history, and no one believes it. The author of the book only wrote a few words about it."

"But what our eldest grandson said today, I feel is not groundless."

In fact, regarding the American continent, many later opinions believe that the earliest discoverer was not Columbus or Magellan, but the Central Plains, or even the pre-Qin period.

For example, the records in the Shanhaijing Dongshanjing, such as hieroglyphics and so on.

Of course, from a geographical point of view, this possibility is not impossible.

Crossing the Pacific Ocean is impossible, but crossing the Bering Strait is not a big problem. Even an ordinary ship can cross it in two or three days.

Zhu Ying did not expect that the old man was so knowledgeable. He just made up a pretext to mention the American continent, and there were actually some sporadic records, which were even read by Zhu Yuanzhang.

"It has existed in ancient times, and it should be possible in the Ming Dynasty. I would like to send an expeditionary force to this place to find the weeping tree."

The atmosphere had reached this point, so Zhu Ying naturally spoke.

Zhu Yuanzhang naturally did not object, and reminded him again: "As the saying goes, a big reward will attract brave men. Since this tree is so important, our Ming Dynasty can also issue a reward to find this tree."

Zhu Ying nodded, this was indeed a solution.

Even if it's a blind cat catching a dead mouse, there might be a certain possibility.

Rubber plays a huge role.

If there really were rubber trees, then the current industrial system of the Ming Dynasty would undergo a qualitative upgrade.

Not just on steam engines.

For example, there will be great progress in vehicle tires, the production of flintlock rifles, and other aspects.

This is enough to rapidly increase the current Ming Dynasty's industry and surpass the world.

The next day.

Zhu Ying directly issued a notice and spread it throughout the country.

A reward of 10 million strings of precious coins or 10 million taels of silver is offered to find the Weeping Tree.

If anyone could produce living offspring and present them to the Ming Dynasty, he would be granted the title of Marquis of Wanhu and a residence in the capital.

As soon as the notice was released, the whole city was shocked.

Because this time the bounty is not only within the Ming Dynasty, but also within the "whole world".

In other words, no matter who you are, from what nationality or what country you are from, you can get this reward.

The specific description of the rubber tree is also stated in detail in the notice.

Ten million taels of silver, plus the title of Marquis of the Great Ming Dynasty, such a reward is enough to drive everyone crazy.