Fifty-five strong men, Lv Bu showed off his skills, bows and crossbows were all perfectly prepared.

  The three of them arrived at Ou Zizhu's home. In front of Ou Zizhu's house, there was a gate that led to the blacksmith shop. After passing through the front yard, they came to where Ou Zizhu lived, and behind his residence was another yard. The three of them went into this back yard. This back yard was quite spacious. On both sides were houses, in front of which were sheds with strange objects underneath.

  The Westerner retrieved a crossbow from a house in the backyard and handed it to Lü Bu, who was overjoyed upon seeing it. The crossbow was slightly larger than the one Lü Bu used on horseback, with a hardwood body and an iron bow that had tremendous pulling power. The string was made of animal tendon, and the body of the crossbow was shaped like an inverted triangle, with three grooves for arrows that fanned outwards. Additionally, there was a copper frame at the rear of the crossbow, which consisted of two parts: one part formed a triangular structure on one side of the crossbow's body, while the other part had a movable slot that connected to the middle of the handle. The other end of the frame was hook-shaped and could be used to catch the string. When the handle was pulled, it utilized the principle of leverage to easily draw the string back onto the bow. Lü Bu realized upon seeing the copper frame that it was designed to assist in drawing the string, and he was secretly amazed that the Mohists had already understood the principle of leverage.

  Lü Bu was delighted, and hastily called Ou Xingzi to bring three crossbow arrows. Without needing Ou Xingzi's guidance, he operated the crossbow himself, loading the string with an arrow and shooting at a wall about thirty or forty paces away. A loud "thud" was heard. The three arrows were embedded in the wall, each one entering to a depth of more than four inches. Lü Bu exclaimed with great joy, "This is indeed a fine weapon!"

  "Ha! This crossbow was made by me in my spare time. The bow is forged from the hundred-fold steel of our family's secret technique, and the string is made from ox tendon infused with nine medicines a hundred times. This crossbow has the power of ten stones, so ordinary people can't pull it open, that's why I added a hook to assist in pulling the string. Within two hundred steps, this crossbow can pierce through a person's body, and three arrows can be fired in a scattered formation, with each arrow spaced one and a half steps apart at a distance of two hundred steps."

  Lü Bu praised: "This crossbow is indeed a rare talent. If we equip our army with this crossbow, haha, the Xianbei tribes will not be far from destruction."

  "The young master needn't worry, I will do my best to assist you in pacifying the world."

  Lü Bu asked again: "Hm, I wonder if the craftsman can improve this crossbow a bit. If it can shoot ten or eight arrows at once, that would be even better."

  "Hahaha... My lord, you don't know this, but I've also thought of this method. After multiple verifications, I found that only one crossbow with three arrows is the best. The more arrows there are, the greater the arc will be. If we arrange the arrows too densely and shoot at one place, it's a waste of crossbow arrows. If the arc is too big, although the arrows are scattered, because the distance between the two sides' crossbow arrows and the center point of the crossbow is too large, it loses power and accuracy. The shot arrows have no killing power, which is also a waste of arrows. Therefore, one crossbow with three arrows is the best."

  Lü Bu was impressed: "Ziying is a meticulous person, I don't understand him, and my words were wrong. From now on, this crossbow will be used exclusively by my elite cavalry."

  Yuwen Ke ordered the craftsmen to take this crossbow as a model and prepare one hundred steel crossbows for Lü Bu's elite cavalry. Lü Bu named this crossbow "Ji Zi Nu".

  Lü Bu then said to Zhang Liao, "This crossbow is not ordinary, and in the future when equipping the army, we must establish military orders again. This crossbow is of the highest quality, each one must be engraved with a number, and recorded on file. Whoever holds this crossbow, if the person dies, the crossbow will be lost. But it cannot be called an external flow."

  Zhang Liao replied: "This general will take note of it."

  Lü Bu saw many weapons in Ou Xingzi's backyard and came to a large crossbow, asking: "Why is this crossbow so big?"

  "Ah, this is a crossbow, converted for defensive purposes. Its power should not be underestimated, it can only shoot one bolt at a time, and the bolt is made from a tree trunk as thick as an arm. Within 150 steps, those who are hit will either die or be disabled, and it can pierce through tens of people along with their horses."

  Lü Bu burst out laughing: "Haha... If we have this cart of crossbows, why worry about the Xianbei bandits on the border? Wen Yan, remember to prepare more of these carts at the passes and cities outside the Great Wall. If the Xianbei invade again, let them come but not return."

  Zhang Liao had been watching from the side with great pleasure and hastily responded: "Yes."

  Lü Bu walked up to a strange object and asked: "I see that this is the largest vessel in the Qi family, but I don't know what it's used for?"

  Ou Zizidao said: "This thing is called a catapult, it can throw large stones from the grinding disc to over 100 steps away. When used for attacking cities, it can smash city walls and gates."

  Lü Bu thought: So this is a catapult, it's so big. Can it also be used to defend the city? Lü Bu looked at the catapult's stone-throwing bowl while stroking his chin. Suddenly he had an idea and said: "Ah, this thing can also be very effective for defending the city."

  "Haha, my lord. This thing is actually for attacking cities. The Mohist school has the way of attack and defense, where there must be defense if there is attack, and vice versa. The crossbow cart is used to defend a city, so the trebuchet is used to attack a city. If you use a trebuchet to defend a city, it won't work well, and even though the large stones thrown by the trebuchet can crush people, they are not very useful and will be wasted. Defending a city still requires crossbow carts."

  "No. The thing is dead, the person is alive. Although the instrument has its specialty, it should also take the person as the foundation. When people are alive, things are used. What Zishi said was that the stone-throwing machine threw a large millstone. If you put it on the city wall and throw goose eggs or fist-sized stones, one throw can be two or three dozen pieces. That is a scattered shooting device to kill enemies."

  Ou Zhi's eyes lit up with sudden understanding. He exclaimed: "Ah! Master, you are indeed a wise and astute person. I, Ou Zhi, have been remiss in my duties. Thank you for your kindness. From now on, I will focus on improving the stone-throwing machine's base plate. With this improvement, the stone-throwing machine can also become a useful tool for defending the city."

  Lü Bu nodded and asked, "The crossbow and catapult are good, but just now the prisoner said that the range of these two things is only one or two hundred steps. I wonder if it can be shot further?"

  Ou Zizi smiled and said: "The range of these two objects is calculated by the number of people, if you want to shoot further, it's naturally possible, but every step forward requires more manpower to pull and throw the pole. The quality of the son is calculated based on the number of people, five people per car crossbow, eight people per throwing stone machine. If there are many people, it's actually not easy to operate."

  Lü Bu heard this and thought about how to reduce the weight of the object being pulled, while also increasing its range. He thought for a moment and then said: "I have a method, let the princes discuss it."

  "Sir, you are wise and clever, what advice do you have, please speak quickly."

  Lü Bu then asked Ou Xingzi for some writing instruments and drew gears and pulleys on a wooden board. Unfortunately, Lü Bu was not good at designing, if Yan Ni were here now it would be better. However, Ou Xingzi and others only drew on one side of Lü Bu's drawing while explaining the other side, thus understanding the ferocity of the gears and pulleys. He then happily said to Lü Bu: "My lord is truly the master of my Mo School, truly a blessing for me."

  Zhang Liao followed Lv Bu for the whole afternoon, often seeing Lv Bu's true nature. In his heart, he secretly rejoiced that he had truly met a lord like Cao Cao, and his mind was made up to follow this lord to the death.

  Lü Bu and Ou Xingzi worked together like fish in water, discussing and improving the equipment of Ou's household, and then manufacturing equipment for the military. Lü Bu also ordered Ou to design a crossbow for Gao Shun's orphan army, which was larger than the horse crossbow but had a longer range and greater power. He also used gears and pulleys to increase the range of the cart crossbow and the stone-throwing machine, reducing the number of people needed to operate them. The two men also improved the crossbow arrows, changing the arrowheads to triangular pyramidal shapes, increasing the wound area, and making it difficult to pull out the arrowhead after being shot.

  Lü Bu then used Xun Yu's management model in the north to manufacture military equipment with streamlined operations, not only keeping Ou Yezi's fine craftsmanship confidential but also increasing production speed. Moreover, Lü Bu used Ou Yezi's ancestral secret technique of hundred-forged steel to forge suitable weapons for each of his main generals.