Gongshu Can immediately said, "Your Highness, please look."

Liu Tan followed him and found two wrench-like objects next to the moldboard plow. He was very sure that these two objects were not on his drawings, and he didn't see them when he looked around just now.

Gongshu Can said, "There's a capstan inside this handle. Turn the handle in a fixed direction, and the plow underneath will lift up."

As he spoke, he turned the plow with force. Liu Tan noticed that the plow body was lifted out of the soil little by little with his movement, until it was completely separated from the soil.

Then he saw Gongshu Can pull out a wooden stick from below. This wooden stick had been hidden inside the plow frame before. If it weren't for the pull ring on the outside, it would be impossible to tell that there was a wooden stick here.

The function of this wooden stick is to fix the handle so that the handle will not turn over if the operator lets go, causing the plow body to drop again.

This fixing method is very primitive, but it works well.

After letting go, Gongshu Can said to Liu Tan, "Your Highness, please follow me."

Liu Tan followed Gongshu Can to the other side of the moldboard plow. There was no handle on this side, only a ring.

Gongshu Can stretched out his hand, grasped the ring and pulled it outwards. Suddenly a section of the ring came out, revealing a wooden stick with four long wooden planks inside. These four long wooden planks only occupied a very small part of the stick, and the rest was just an ordinary wooden stick.

Gongshu Can explained: "This is used to control the plow body. As long as it is rotated in a certain direction, the plow body will also rotate."

As he explained, he slowly turned the ring. Liu Tan indeed saw that the plow body below also began to rotate slowly. After it turned to the completely opposite direction, Gongshu Can stopped and reinserted the ring. The plow body then maintained the direction it was facing after rotation.

At this time, Liu Tan also understood that the long wooden boards fit perfectly into the slots inside, maintaining the position of the ring after rotation, which was equivalent to maintaining the current direction of the plow body.

Gongshu Can walked over again and lowered the plow body again, and the rotation of the plow body was completed.

As for the traction frame, it is actually simpler than the plow body. The two traction woods of the main body do not need to be moved, and a rotating shaft can be installed at the connection between the traction frame and the plow column. The same is true for other places. It is equivalent to taking the plow column as the main body and keeping it stationary, and the traction frame flips back and forth horizontally on it.

The flipping mechanism of the traction frame is very simple, but what makes Liu Tan curious is how the two mechanisms operate the plow body?

In other words, he could understand the mechanism that lifted the plow body just now. It was nothing more than a rope tied inside, and the rope was fixed on a rotating rod. When needed, the rotating rod was rotated. The principle was probably similar to that of a well wheel.

But how do you control the rotation of so many plow bodies at the same time?

Gongshu Can may have seen Liu Tan's confusion. He glanced at his son and immediately went to get a sample that they had made before.

Gongshu Yi dragged the tray, and Gongshu Can quickly disassembled the sample, revealing the mechanism inside.

It was only then that Liu Tan discovered that there was a disc on each plow body with a wooden pole fixed on it, and this wooden pole was connected to a vertical wooden pole through a rotating shaft, and the vertical wooden pole was connected to another rope through a rotating shaft. The other end of the rope was the ring that just operated the mechanism.

At this time, the two wooden poles and a rope are in an inverted Z shape. When controlled by the ring, the rope is wrapped around the wooden pole inside the ring, gradually pulling the two wooden poles. This force pushes the bottom disc to rotate, so that it reaches the desired position.

If you want to return it to its original position, just pull out the ring and rotate it in the opposite direction.

The wooden pole inside the ring runs across the entire moldboard plow, and the ropes are fixed at corresponding positions according to the spacing of the plow bodies, so that these plow bodies can be steered at the same time.

The principle was actually very simple, but Liu Tan couldn't help but laugh and said, "That's a good idea. What made you think of this?"

Gongshu Can thought for a moment and said cautiously, "Actually...I did this for the benefit of the common people."

He felt a little nervous after saying this. His Royal Highness the King of the North must have improved the plow for the people. He seemed to be denying the other party's approach by saying this, but he had not learned how to speak tactfully over the years. After thinking about it, he just said it directly.

This is just his personality. He can pretend for a day or two, but if he is accidentally exposed after a long time, it might even make His Royal Highness the King of the North unhappy.

It would be better for him to take advantage of the fact that His Royal Highness the King of the North still has patience with him and reveal his own shortcomings. This way, at most he can go home, but at least he can still keep Gongshu Yi.

If they anger the King of the North, the entire Gongshu family will probably be fired.

Liu Tan was not angry. He knew his own shortcomings and was not down-to-earth enough. The era he lived in could be regarded as a fairyland for people of that era. After he traveled through time, the living standards had always been very high, so he was not sure what the people needed.

He nodded and said, "Go on."

Gongshu Can's confidence soared. He said, "I once thought of replacing these parts with bronze or iron. However, if I did, this plow would be worth a fortune. Even if only the plow body was made of iron, it might not be affordable for ordinary people."

Liu Tan nodded. This was actually what he had always been worried about. Even if the Northern Border Kingdom's iron control was not so strict, it did not mean that everyone could afford a moldboard plow with an iron plow body.

"So what do you mean by that?"

Gongshu Can said, "Many people still use stone plows. This plow can also be replaced with a stone plow body. However, a disadvantage of a stone plow body is that it breaks up soil and digs trenches much worse than an iron plow body. Therefore, it is definitely not enough to just plow once. In this case, two or three passes are needed. If it is a single plow, it is simple, but a large plow like this is very troublesome to rotate it."

Lu Xuan, standing by, asked curiously, "Since you can afford a large plow, why can't you afford an iron plow?"

This time, even without Gongshu Can, Liu Tan could explain: "If the plow body is replaced with a stone one, the cost of these two iron plow bodies alone would be as much as the entire plow."

Lu Xuan nodded in understanding. He had not previously had a clear understanding of the various prices in the Han Dynasty. However, in the Wusun Kingdom, due to the scarcity of trees, wooden tools were not much cheaper than those made of bronze.

He originally thought that the Northern Border Kingdom also lacked trees, perhaps just like Wusun, but now it seems there are some differences.

Liu Tan said with a smile: "Your improvement is very good, reward!"

Liu Tan had already prepared a reward for Gongshu Can, but he didn't expect that he would make some improvements, so he could only add a few pieces of cloth on the spot.

Gongshu Can listened to Bigao's long list of last times and was stunned to find that these rewards were enough for their family to live for many years!

After walking around, Liu Tan suddenly had an idea and said, "Actually... plowing and sowing should be possible at the same time."

Gongshu Can was already stunned by the money and hadn't reacted yet: "Ah?"

Gongshu Yi had already received numerous large rewards from His Royal Highness the King of the Northern Territory, so he managed to calm down and ask, "Your Highness means..."

Liu Tan asked, "Can the harrow be combined with this plow?"

Gongshu Yi was stunned for a moment: "A plow cart? What is that?"

Liu Tan was surprised: "You don't know?"