Goguryeo, began in 37 BC Buyeo Prince Zhu Meng in Liaodong to establish a secession regime, during the period of the Sixteen Kingdoms, Goguryeo had and Murong Xianbei's former Yan to compete for the hegemony of Liaodong, almost by the Murong clan to destroy the country, and later Murong put the main force to the Central Plains battlefield, Goguryeo escaped.

After the decline of Murong Xianbei, the vacuum in the eastern Liaodong region was quickly filled by Goguryeo, and during the Northern and Southern Dynasties, the territory of Goguryeo stretched from Liaoshui in the west, the Sea of Japan in the east, the Huifa River in the north, and the Han River in the south.

The Book of Sui records: 2,000 miles from east to west, more than 1,000 miles from north to south.

Different from the nomadic people who rose on the grassland, Goguryeo had a very high degree of sinicization, and during the Wuhu Rebellion, they absorbed a large amount of advanced technology from the Central Plains, and sat on the rich iron ore resources of the Liaodong Peninsula, so they could "use bows, arrows, swords and spears as soldiers, and each family has its own armor" ("Book of Wei").

At that time, Goguryeo had a cavalry army with horse armor and a horse lance. In addition to the armor cavalry, the Goguryeo cavalry archery troops were also very strong, because the Liaodong region was rich in forestry resources, and the style of hunting was prevalent, and they were rich in a compound bow called the "貊mO bow", which was short and powerful, and was extremely suitable for riding and archery.

The most terrifying thing about Goguryeo is that it also has a very terrifying military mobilization ability, with 600,000 troops at its peak, tens of thousands of armored cavalry ("History of Chinese Goguryeo") and Zhenguan nine years, the total number of soldiers of the Tang Dynasty is only 800,000.

Therefore, Goguryeo has never been a weak chicken country, and you must not think that it is also a weak chicken because it is very similar to the name of a certain country in later generations.

In the nineteenth year of Zhenguan in history, the Tang Dynasty, which was at its peak, Li Ke's father Li Shimin personally conquered Goguryeo, and captured "100,000 horses and cattle, and 10,000 leaders in Mingguang armor!" (New Tang Dynasty Book)

This is also one of the reasons why Emperor Yang of the Sui Dynasty conquered Goguryeo three times and finally failed, and whether it was Emperor Yang of the Sui Dynasty or Li Shimin, it was very clear that Goguryeo was a big problem for the Central Plains Dynasty, so the Tang Dynasty in history adopted a completely different tactical method from Emperor Yang of the Sui Dynasty.

The Tang Dynasty has now learned the lesson that Emperor Yang of the Sui Dynasty wanted to complete his work in one battle, and was finally dragged to death by the long supply line, and after the four years of Zhenguan to eliminate the Eastern Turks and survive the initial disaster, the Tang Dynasty began to play a war of attrition with Goguryeo.

Since the fifth year of Zhenguan, the Tang Dynasty has continuously sent small forces to reconnaisance in the territory of Goguryeo and began to explore and plan the terrain.

Later, after Li Shimin's personal conquest, he gradually became a large army, not pursuing to conquer the city, but the large-scale implementation of the scorched earth policy, destroying production, weakening national strength, and dispersing the hearts of the people, this policy has been continued from Li Ke's father's Taizong Dynasty to Li Zhi's Gaozong Dynasty, and then Goguryeo, unable to hold on.

This tactic is not very familiar, in fact, this is somewhat similar to the strategy that the nomads have always implemented against the Central Plains Dynasty, and the Tang Dynasty and Goguryeo are playing with national strength.

To tell the truth, if it weren't for the Tang Dynasty, which was also at its peak, in front of Goguryeo, but any country with weaker chickens, Goguryeo could be like the Northern Wei Dynasty, with troops stationed in the north, and then enter the Central Plains.

And now, for Li Shimin, Goguryeo is a big problem.

"How do you target the heavy cavalry?" Li Shimin sat up straight, and so did Li Chengqian.

"Dad, you should have seen it tonight, my fireworks can probably shoot at a height of about 150 to 200 meters." Li Ke said.

"M?" Li Shimin frowned.

"Oh, this is a brand new unit of length invented by Erchen, all of which are in the decimal system, and some of the current length weights and measures conversion in Datang are too complicated to be promoted." Li Ke said helplessly, "But at present, Erchen has not announced it to the people, but his own craftsmen are using it." About three feet is one meter. ”

Li Ke gave an approximate conversion ratio, and Li Shimin knew the height.

"Dad, think about it, if I am on the battlefield and the enemy's heavy armored cavalry rushes over, I use this thing to aim at the enemy's cavalry, lay down sideways and shoot at the enemy, what kind of scene it will be." Li Ke said.

Li Shimin pondered for a moment, and then asked, "It's loud?" ”

"Yes, it's very big, although the color is not conspicuous during the day, it will also make a loud noise, but in fact, when it explodes in the air, if it is placed on the ground, a person without armor stands nearby, it may be killed directly, that is, it has a certain lethality."

"If I put some broken iron filings or pieces of iron inside this firework, it will explode more powerfully!"

"Of course, I don't expect it to kill people directly, but the enemy's war horse has not been trained like this at all, and once it is so confrontational, the opponent's cavalry formation and war horse will be shocked!" Li Ke didn't describe too much here.

Li Shimin fought on horseback, and of course he knew very well what kind of results would be caused by the frightened horses when the cavalry charged on the battlefield, and it was also a large-scale frightened.

If our war horses have been trained again, at this time, it will be a slaughter for the other party.

"Good thing, but why did you take it out, shouldn't you make it secretly?" Li Shimin asked.

"It's okay to make secrets, but its sound is not small, and it's not convenient for us to train war horses, so Erchen disguises it as fireworks, so that when training war horses in some places in the future, it can also be said to celebrate marriage, or other happy events, festivals, etc., anyway, the excuse is easy to find." Li Ke said with a serious face.

Li Shimin looked at him suspiciously, are you sure that's the case? Not because fireworks are fun?

"Of course, there is another reason that it is made into fireworks, so that no matter what festival, if we set off fireworks in large quantities, we can increase the production of gunpowder inside, which is conducive to training a large number of skilled workers, after all, if you use enough, you can produce more, and even improve."

"If we just produce it secretly and don't use it, we don't know how effective it is, we can't figure out its performance, the rate of improvement is slow, and the training of workers is slow." Li Ke added.

Li Shimin nodded silently, this is a fact, Li Ke has always been thoughtful in this regard, and this is a good consideration.

"Okay, even if you did a good job, what do you think?"

"Father, the son thinks it's okay to leave it to San Lang to be responsible, and when we are ready to use troops on a large scale against Goguryeo, then San Lang will take it out directly, and the cavalry that should be trained will be trained secretly." Li Chengqian thought for a while and said, this matter is not suitable for anyone other than Li Ke, because other people are really not as easy to keep it a secret as Li Ke.

Li Chengqian didn't know how loyal Li Ke's business houses were, but Li Chengqian knew one thing, that is, San Lang used those craftsmen from ordinary backgrounds, ordinary people, etc., not to mention whether there were people in them, and these San Lang people could be said to be very kind to them.

As a crown prince, Li Chengqian knows the family and the people very well, and he knows very well that because of various interests, if they are handed over to some people who have the power of the family behind them, they will never be able to escape the kidnapping of interests, but Li Ke here, those craftsmen and people under his command, if you put a knife on their necks, they may not be able to say.

That's the big difference.

"Okay, then forget about this matter, you go and play a few rounds of mahjong with your mother, and your sister and they are waiting for you for a night." Li Shimin glared at Li Ke and said.

"Yes, Erchen went." Li Ke stood up with a grin.

There is not much problem with the vigil in the second half of the night, in fact, everyone pondered the vigil, so yesterday they all made up for sleep during the day, although they were a little sleepy, but a group of people played, and they were not so sleepy.

Today's court meeting is very early, and it is also very long, because the scale is large, such as some princes who usually do not go to the court will go to the court, among these people are Li Shimin's brothers, uncles and the like, anyway, it is the clan of the Tang Dynasty.

Many of them don't have specific positions, but today they are all going to the court.

Similarly, the envoys of various countries in Honglu Temple will also come to the court today with tributes to congratulate Li Shimin.

All in all, today is the Good Friday of the officials of the Ministry of Rites, and as for Li Ke, he simply hid behind Li Chengqian above the court, and then leaned on the back of his chair and began to nap.

From his point of view, it is not easy for the ministers below to find out, but Li Shimin, who is sitting on the throne, sees it clearly.

Fortunately, the envoys of various countries will not be so far forward in the court, so they probably won't see it, but the corners of Li Shimin's mouth twitched endlessly, Lao Tzu played mahjong all night, sitting here at this time, and the waist still needs to sit straight, I'm not tired, are you tired?

Lao Tzu wanted to let you go, but you made Lao Tzu angry by yourself, so you can't blame Lao Tzu for being ruthless and unrighteous.

Li Chengqian is also a little helpless, the third child, you are really a model of my generation, you dare to do anything.

The long court meeting finally ended about halfway through the morning, and it was not easy to do more than two hours.

"Wait, one last thing I'm announcing." Seeing that everyone was tired, Li Shimin spoke slowly.

"Li Ke, the king of Qin, was dedicated to having fun yesterday and invented fireworks to celebrate Yuanzheng, which was harmless, but he didn't want to inform the court in advance, causing the people of Chang'an City to shake and panic, so he punished Li Ke, the king of Qin, to assist me in handling state affairs for two months after the end of the Shangyuan Festival, and was not allowed to take a vacation, so as to set an example." Li Shimin said lightly.

"Huh?" Li Ke, who had just been confused for a while and had a much clearer brain, heard Li Shimin's words, and his whole person was like being hit by five thunders.

Who the backstabbed me? This is a move that Lao Li can come up with? I don't believe it! Who the hell came up with this trick?!