I can't imagine that there is such a hard thing in the world, but fortunately, Li Shimin interrupted this gamble, otherwise I am afraid that I would have died here today! Touching the city wall that was not favored by himself, Hou Junji was afraid for a while.

But he couldn't figure out how he did it? Even a ballista can resist it.

The stone is not like a stone, and it is not like a brick, and the whole city wall is like a whole, and there is not the slightest trace of masonry.

"What the hell is this?" Li Shimin is not much better than Hou Junji, but Li Shimin is not afraid in his heart, but shocked and happy.

After seeing the hardness of the concrete fortifications, Li Shimin's first thought was to use this thing to cast several large military forts in the north, with thousands of soldiers stationed in them and millions of stones of grain.

Before that, there were not many military material reserves in the border fortress city, mainly because it was too laborious to build a fortified city defense in the border pass, and the border pass city was unstable, and no matter how much grain was stored, it could only be the enemy, so the military rations in the north could only be stored in Youzhou, Xiazhou, and Shengzhou, which were a little farther away from the border, and there were also a large number of garrisons in these three places, no matter which direction was attacked by the enemy, the garrisons in these three places could rush to the border pass within a few days.

But what if there was a city that was hard enough for the Turks to impregnate? Only need to build a large city in Lingzhou, Fengzhou and other places, and build two military forts in the rear that can be defended by thousands of people, and the three cities are horns of each other, will the Turks still dare to attack?

Li Shimin's first thought is military value, if you want to settle down, you must first solve external concerns, but ......

Li Shimin thought of another question, and frowned slightly: "What is the price of this thing?" Is the quantity sufficient? ”

If the price is too high and the quantity is insufficient, the previous idea will have to be abandoned.

Of course, Li Shimin is most worried about the quantity, and as for the price, hehe......

"This thing was discovered by the king by accident, named cement, after seven days of processing, finally in the form of powder, mixed with other materials, stirred into a pulp, in summer it only takes three or four days to completely dry, in winter it takes ten days or more. As for the price, this is not expensive, a total of 3,300 stone was processed, at the beginning of the time converted into a stone consistent money, and later mastered the skills, improved the process, a stone will be 500 yuan, and the latest batch of cement, a stone cost is only 300 yuan. Li Yuanji smiled slightly, talking serious nonsense.

"So, in less than seven days in the summer, a city can be built?" Although Li Shimin was reluctant to believe it, he still asked with hope.

Three hundred yuan per stone, which is not even as good as the current price of grain, this price Li Shimin does not think it is expensive, but if an entire city needs to be built with this cement, how many stones should be used?

But what Li Shimin is most concerned about is the speed of building the city.

"If there are enough materials, enough labor, and the speed can keep up, it is possible to build a city in seven days. The city gate tower in front of me, because of the need for design improvement, the arrangement of some fortifications suitable for actual combat, a lot of time was delayed in the middle, and the labor was only more than 40 people, and the time was only half a month. Li Yuanji explained with a serious face.

"What about cement? How much did you use? ”

"The cement only used less than 500 stones, including labor and other costs, it took half a month, and it cost about 200 yuan." Li Yuanji's frankness shocked everyone.

Such a large city gate tower only took less than 200 yuan?

The length and width of this city tower is about ten zhang (about 30 meters), and the city does not need to build four sides, the four sides are folded, it is forty zhang long, and the Turks do not have a siege weapon, and they are not good at attacking the city, so the military fort of the border pass can not be set so high, three zhang can be more than enough, and the cost of height and gatehouse savings can be folded into ten zhang, that is, the price of 200 guan can build a section of the city wall that is fifty zhang long and three zhang high.

And a military fort with a length and width of 500 zhang can accommodate tens of thousands of soldiers, and a section of the city wall with a total length of 2,000 zhang only needs 8,000 guan. Fang Xuanling snapped his fingers and secretly calculated the account.

But the more he counted it, the more shocked Fang Xuanling became.

About 10,000 guan can build a city at the border, although the price is a little more expensive, but it only takes three months at most to complete, and the ordinary city construction, just that section of the city wall, it takes three or five years, more than decades, and the manpower and material resources required are countless.

So if you calculate it carefully, the price is still very cost-effective.

Of course, Li Shimin's mathematical skills are not very good, and even Fang Xuanling's mathematical skills are not very good, otherwise such a simple arithmetic problem would not have to count for half a day with his fingers.

But even if he doesn't calculate the cost of the city, Li Shimin knows very well that it is still very cost-effective to build this new type of city.

glanced at Li Yuanji quietly, and the hated Li Shimin was a little itchy.

'Damn, why you?' Why can't it be someone else? ’

If someone else discovers this kind of material, Li Shimin will definitely not hesitate to take it back to the imperial court, and what the imperial court pays is at most a reward and a title.

It can be found that this material is Li Shimin, the title or something will not work, and it is impossible to take it by force, if he wants to rob the things of King Qi, he Li Shimin's reputation is afraid that it will be completely lost for 10,000 years.

There are inconsistencies between the inside and the outside, this is a compulsory course for an emperor, who has been the king of Qin for so many years, has encountered so many flying disasters, Li Shimin has long practiced this skill.

"Now that the treasury is empty, I'm afraid that I won't be able to come up with so much money and grain, so Yuanji must make persistent efforts to lower the price as soon as possible." Li Shimin said with a smile on his face, Li Shimin never believed that the cost of cement would be so high, but on the surface, he had to believe it.

Similarly, Li Yuanji's actions once again made Li Shimin feel deeply threatened.

He is about to ascend the throne as the emperor, what is Li Yuanji's purpose in making such a show at this time? Li Shimin is puzzled, many people are puzzled, anyway, they will never believe it, Li Yuanji just wants to sell his cement.

Li Shimin quickly left Taipingfang with a group of civil and military ministers, coming in a hurry, with a solemn face, and leaving in the same hurry, with a still heavy complexion.

However, the meaning of the two is completely different, when you come, you are confused, and when you leave, you have your own thoughts.

Song Zhong hadn't even figured out the ins and outs of the matter, and what was Li Yuanji's purpose? Li Shimin had already left in a hurry, leaving only Song Zhong and Yu Ren with a confused face, and of course, Luo Chen, who was always half a beat slow to react.

"Okay, everyone is gone, what are you doing in a daze? Hurry up and gather the workers and continue to work, and when the weather is cold, this work will not be easy to do. Interrupting the confusion of the three of them, Li Yuanji walked to his temporary nest, there is nothing more comfortable than his own nest.

"Your Highness, what do you mean by this? Why can't the slave and maid figure it out? Yu Ren, who realized it later, hurriedly followed.

"What do you mean? You losers have almost finished giving this king's family wealth to Huo Huo, if this king doesn't want to make some money, is it possible that he plans to sleep on the street in the future? Li Yuanji pretended to make a gesture and glared at Yu Ren fiercely.

Loser? Am I a loser?

Yu Ren, who was frightened by Li Yuanji's eyes, stopped there trembling all over, and a monstrous sense of grievance arose spontaneously in his heart, His Royal Highness actually said that I am a loser?

Ignoring Yu Ren's grievances, he called Song Zhong and whispered a few words to him, Song Zhong secretly nodded his head, and then left quickly.