I directed the Xuanwumen Incident

Chapter 491 A Heavenly Official Who Appears Every 500 Years?Li Chunfeng!

Kakaka.

The wheels rolled, raising clouds of smoke and dust.

Xu Fenglei in the carriage looked curiously at the young scholar in front of him.

"You are Li Chunfeng?"

He said with great interest,
"The one in charge of Qin Tianjian?"

This trip is under the order of Li Shimin to go to the palace to have an audience.

Unexpectedly, there was another person along the way, and this person was Li Chunfeng, whom Xu Fenglei had always been interested in.

This one, according to legend, is a "Heavenly Official" who comes out once every 500 years. Seriously, he can be regarded as the ancestor of my former fortune teller!
"The next official is Li Chunfeng."

Li Chunfeng looked a little cautious, bowed his hands and saluted,
"I have met Grand Master Xu Gong."

"It's true that the lower officials are also serving as the Qin Tianjian, but they mainly work in the Taishi Bureau, and they are generals."

Xu Fenglei nodded slightly.

"Oh yes, it's Taishi Bureau."

he laughed,
"The Taishi Bureau is in charge of astronomy, geography, calendar making, and history revision. No genius is competent."

"Brother Chunfeng, you are a rare talent in a hundred years!"

Li Chunfeng praised this and waved his hands again and again.

"How dare you dare... The Grand Master is absurd."

He hurriedly said,
"The next official is just doing his job well, not a genius."

"A person like Mr. Xu is the real pride of heaven..."

He was a little flattered by this sudden compliment.

"Hahaha, I can't talk about it. I'm just lucky. In fact, I'm very good at it."

Xu Fenglei laughed loudly, waved his hands and said,
"Let's not be so polite, you and I are about the same age, just call them brothers! I hate this honorific title and that honorific title the most, it adds distance for nothing."

"I heard that you have a deep research on Yili, and you are also very good at numeracy. You are the number one mathematician in the world."

"It's boring all the way, why don't we discuss it?"

Li Chunfeng's eyes lit up.

He is not good at interpersonal communication, so he is a little rushed, but when it comes to academic discussions, then he is not sleepy!
"I have heard that Mr. Xu is easy to count everyone, and Chunfeng has been friends with him for a long time."

Li Chunfeng kept saying,
"Don't dare to talk nonsense, and ask Mr. Xu for advice."

He no longer called himself a lower official, but he still used the honorific title for Xu Fenglei.

After all, the two have just met, and you can't take it seriously if they are polite to you. You really call him Brother Fenglei, right?

He's not good at people, but he's not stupid.

"well……"

Xu Fenglei nodded and asked,

"I heard that you are good at watching the sky to know the world. I don't know much about the relationship between astronomy and Yili, and I have never watched the sky."

"This is a blind spot in my knowledge. Can you tell me about it? It's fine if it involves confidentiality."

Although it was said that Li Chunfeng 'asked' him, in fact, it was he who was asking Li Chunfeng for advice.

Just kidding, he is a heavenly official who comes out every 500 years!
I am just a little guy in the area of ​​numerology and easy counting. At most, I can rely on the prophetic advantage of the traverser to be able to tell the truth, which is far worse than others!

Now that I have the opportunity, I naturally want to ask for advice!
"There is nothing secret or not. If Mr. Xu wants to know, Chunfeng will tell you everything."

Li Chunfeng said with a smile,

"Mr. Xu once heard that Fuxi observed the sky and the earth, and deduced the innate gossip."

"Wen Wang wrote "Book of Changes" on this basis. At the same time, Lianshan, Guizang and other Yi studies works emerged."

Xu Fenglei nodded.

Of course he knows these basic common sense,

"So, astronomical phenomenon is the foundation of Yi learning, and it can even be said to be the origin."

Li Chunfeng said in a deep voice,

"But with the passage of time, since Zhou, more and more works on easy numbers have emerged, and they have become more and more complicated."

"The origin is also becoming more and more blurred."

"Therefore, compared to the methods of divination, prediction, and deduction derived from various sources, I prefer observing the sky. Because it is closer to the source, and naturally speaking, it is more accurate."

Xu Fenglei suddenly understood.

"That's how it is, be taught and be taught."

He hurriedly asked,
"What is the concept of the phenomenon that day? And how do you connect the celestial phenomenon with human affairs?"

Now he looks like a poor student who is receiving extra lessons...

"Personnel affairs, small matters, have few changes, and can be deduced by ordinary judgments; state affairs are extremely complicated and involve many things, so we need to use astronomical judgments."

Li Chunfeng patiently explained,
"Of course, some important people came into being as the times require, and their fates will naturally be linked to the celestial phenomena."

"For example, Your Majesty, such as Mr. Xu, you are all important figures in the Tang Dynasty, and there must be heavenly stars corresponding to them. These are called emperor stars, Xiang stars, general stars, etc."

Xu Fenglei frowned.

"I also have a corresponding star?"

He suddenly became interested and asked.

This is interesting. As a time traveler, he should not belong to this time and space.

If there is a corresponding star, it means...it is also a certainty that I came to Datang?

Thinking of this, Xu Fenglei felt a chill in his heart for no reason, which made him shiver.

"Naturally there is."

Li Chunfeng laughed and said,
"Xu Gong's sudden emergence, with momentum like a rainbow, should be a great help for the country and the country."

Xu Fenglei raised his eyes and glanced at Li Chunfeng. Seeing his deep eyes, he suddenly felt uncomfortable with his underpants being seen through, so he quickly changed the topic and said:
"Haha, let me borrow your good words, I will borrow your good words."

"Brother Chunfeng, please tell me the specific steps of judging the celestial phenomena? I am very interested!"

Li Chunfeng looked away and nodded.

"it is good."

He said in a low voice,

"To judge the law, we must first start with the root of Yi. There are three roots."

"It's not easy, it's easy, it's easy." Xu Fenglei blurted out.

This is the foundation of the foundation.

"Correct."

Li Chunfeng nodded and said,

"The so-called is not easy, the sun, the moon, the stars, and the cycle of the sky have never changed. The sky seen by the ancients thousands of years ago and Fuxi thousands of years ago is the same sky that we see now. God, this is not easy."

Xu Fenglei nodded repeatedly.

"People today don't know the moon in ancient times, but this month once illuminated the ancients."

he read,
"The sun, the moon, and the stars have never been easier."

Li Chunfeng raised his brows.

"Good poem, good sentence."

He praised,
"Xu Gong is still a literary hero and poet."

Xu Fenglei smiled.

Writer?Poetry thief.

To tell you the truth, I will still say "When the moon on the river shines on people at the beginning of the year, who on the riverside sees the moon for the first time."There are endless generations in life, and Jiang Yue looks similar year after year. They all mean the same thing, but I am embarrassed to show it off again.

"The sun, the moon, and the stars are not easy, but they will change."

Li Chunfeng said again,
"The moon waxes and wanes, the stars dim, and the battles turn around. This is their change."

"The frame is not easy, but the inside of the frame is easy, and there is an image. It is like drawing a cat, a tiger, a dragon, and a snake within a picture frame. Astronomical phenomena are like cats, tigers, and dragons in a picture frame." .Snake-like, changing at any time, this is an elephant."

"And with Xiang, you can infer from Xiang, which is easy..."

"..."

Xu Fenglei was as intoxicated as he heard it.

This Li Chunfeng really didn't hide his secrets at all, he directly spoke out the most fundamental essence!

In just half an hour, Xu Fenglei felt that he had made rapid progress!

"Brother Chunfeng, take a break first, I have to find a notebook to write down my feelings..."

Xu Fenglei took out a small notebook from his arms, found a pen from the compartment, and said with a focused face,
"Wait for me, tell me later..."

Swish swish.

At this moment, he is already in a state of diarrhea, and writing his feelings in a book is more refreshing than taking a shower!

"Okay, Mr. Xu, just take your time."

Li Chunfeng smiled lightly,

"Please lend me a piece of paper, the journey is far away, and I just happen to study the next problem that has troubled me for a long time."

chapped.

"Take it, take it!" Xu Fenglei tore off two pieces of paper, and handed it along with a pen.

"Thank you Mr. Xu."

Li Chunfeng took the pen and paper, sat across from Xu Fenglei, and after drawing a few random strokes, he fell into deep thought.

The carriage was bumpy, but the two of them felt nothing, they were both immersed in their own world...

After half an hour.

"call--"

Xu Fenglei threw down the pen, and said with a relaxed face,
"Listening to your words today is better than reading ten years of books!"

"Astronomical phenomena are indeed mysterious, and I have just glimpsed the door!"

"Hahaha……"

Looking at the experience in his hand, he laughed heartily.

Turning his head to look, he saw that Li Chunfeng was biting the tip of his pen, his brows were tightly frowned, as if he was deep in thought.

This scene surprised Xu Fenglei a little.

A genius like Li Chunfeng also has things he can't figure out?

He stood up, moved to Li Chunfeng's side, and looked at his piece of paper.

On the paper, there was a cylinder and half a dome, and on the far right, a ball was roughly drawn.

"Brother Chunfeng, what are you busy with?"

Xu Fenglei said casually,

"Are you calculating?"

"Yes." Li Chunfeng let out a sigh of relief, shook his head and sighed, "I'm measuring the size of the ball. According to the method proposed by Zu Wei, the size of the ball can be obtained only by asking for the size of the Mouhe square cover, because the height is equal. Two objects of the same height with the same cross-section must have the same size, but why..."

Xu Fenglei almost fainted.

"What is the cross-section at the same height, it's a mess and I can't understand it."

he said,

"Isn't it just asking for the volume of the sphere, which is very easy to handle."

Li Chunfeng raised his head abruptly.

"Guild Xu calculates?"

He continued,
"Please enlighten me!"

Xu Fenglei was a little baffled by his sudden arrival, but he also reacted when he saw the longing look in the other party's eyes.

This Li Chunfeng is a master of Yi Xue and a mathematician who loves mathematics!
The essence of Yixue is image and number. It is impossible for a person who is proficient in Yixue to not be interested in mathematics.

"Here, give me the pen."

Xu Fenglei took Li Chunfeng's pen and said,

"To measure the volume of a sphere, there is actually a formula."

"This formula is - V=4/3πR to the third power."

Li Chunfeng was stunned; "..."

"What is V? What is π? What is R? What are the symbols of 3 and 4?"

He was completely bewildered.

Xu Fenglei wrote in a hurry, but he couldn't understand a single word!

"Uh...these are all symbols of reference."

Xu Fenglei helped his forehead, this time it was his turn to explain patiently,
"V means volume."

"3 and 4 are relatively simple numbers, representing three and four, and the others are 0, 1, 2, 5, 6, 7, 8, 9. I have taught the prince and others about these, and I will teach you now , this number will be much simpler, otherwise it would be too troublesome to use Chinese characters, too abstract, which is not conducive to our mathematical research."

Seeing this series of numbers, Li Chunfeng's eyes lit up.

"Replacing one, two, and three with simple symbols? This is indeed a pioneering work!"

He was pleasantly surprised,

"Mr. Xu, you invented this?"

"Uh... I learned it too. The one who invented it was from Tianzhu." Xu Fenglei scratched his head, not brazenly taking the credit for himself, and said with a smile, "There are many religions in Tianzhu, including Buddhism and Tianzhu religion. Various sects often debate scriptures, in order to overwhelm each other, they need to use extremely large numbers to show the strength of their own gods, so... their number skills are also very developed."

Arabic numerals were invented by Indians... well, I should remember correctly.

"I see."

Li Chunfeng clicked his tongue in amazement and said,
"It must be a magical country to be able to create such a number."

"If you have the opportunity, you should communicate with the Tianzhu people."

Xu Fenglei couldn't help laughing secretly when he heard this.

magical country?Ah San's country must be miraculous!
It's just that you can't think of it, there is nothing the third brother can't do.

"Then this π?"

Li Chunfeng looked at the paper again, pointed to the symbol and said,
"What do you mean?"

"This is the meaning of pi, you must know it." Xu Fenglei said, "Liu Hui once used the cutting circle method to get the pi ratio to 3.1416, and Zu Chongzhi made the pi ratio even more accurate to 3 on the basis of Liu Hui. 1415926! Lead the whole world!"

Li Chunfeng nodded repeatedly.

"I know this, it's recorded in "Nine Chapters Suanzhu"."

He praised and sighed,

"Liu Hui and Zu Chongzhi are both unborn masters! It's a pity... Mathematics has never been taken seriously."

"I've always felt that numeracy is actually very important. It is closely related to everything in this world, eh..."

Xu Fenglei raised his eyes slightly.

"You feel right."

He said seriously,

"Mathematics is the foundation of all science and engineering."

"Only when mathematics develops, other things can develop along with it. Therefore, I have plans to vigorously promote and develop mathematics in Datang!"

"In this way, the country can progress!"

When Li Chunfeng heard this, he was immediately in awe.

"Mr. Xu is far-sighted!"

He gave a thumbs up and said,

"If this is the case, it will be the great fortune of Tang Dynasty!"

Xu Fenglei grinned.

"At that time, I need your help."

He patted Li Chunfeng on the shoulder and said,

"In my Chang'an Academy, there are mathematics courses, and there is a mathematics school next to it."

"The candidate for the dean is up to you! Brother Chunfeng."

Li Chunfeng: "?!"

"I...what am I capable of?" His expression was startled, and he was about to decline, but Xu Fenglei held down his hand. "Datang, only you are a well-deserved mathematician!"

Xu Fenglei said seriously,

"The position of dean of mathematics belongs to you!"

"Just treat it as a favor to me, and you don't want to refuse anymore!"

(End of this chapter)