On the New Year of the third year of the Yuan Turtle, the Military Industry Department of Lan Xiang Huadug presented Yu Qiuping with a New Year's gift that made Yu Qiuping ecstatic - a successful imitation of a three-pounder cannon.

After nearly a year of hard work, the military industry department of Lanxiang Huadi finally succeeded in copying the first big tube. Since Chang Panbei barely expanded the army in a year, the production of iron cannons, guns, spears and short knives gradually slowed down, and the Department of Military Industry put nearly eighty percent of its strength into the imitation of large cylinders; And the brothers that Itami Kangqing brought back also taught the drawings and experience that they knew; Coupled with the three large cylinders that Yu Qiuping bought at great expense for them to make test products and a steady stream of experimental funds, the Military Industry Department finally succeeded.

In the course of a year, they made and discarded countless abrasive tools, wasted countless copper, iron and metal, and consumed almost enough money to cost thousands of feet a year. Under the tremendous pressure of the Diet and the Sena clan, Yu Qiupei supported them to carry out the experiment against public opinion, and finally succeeded.

However, in front of the rainy autumn plane, it was still only a pitiful three-pounder cannon with little power - this was the only result of a year's hard work of the Military Industry Division. It has a range of about 300 meters, and it fires only solid iron ball-shaped shells, which can hardly be lethal to buildings made of earth and stone. If it weren't for Lan Xianghuadu's repeated assurances to the Diet and Sena Clan, with the experience and data of the first cannon casting, the cannon casting would be faster and faster in the future, and the cost would be less and less, and the artillery casting plan of the Military Industry Department would have almost been vetoed.

However, it was this three-pounder cannon that became Yu Qiuping's treasure. He had the M.R. build a small gun wagon for the gun, which he would pull on four horses, and generously equipped it with a crew of about 20 men. There were gunners in them - they were also training hard day and night to improve their accuracy and firing speed, just as they had been when Yu Qiuping had trained iron gunners before. There are also coachmen, shieldmen, loaders, and many other auxiliary units.

However, the gunners practiced and practiced, but Yu Qiuping found that something was wrong. No matter how hard they practiced, their level of improvement was always slow, and they could not catch up with half the progress of the iron gunners back then. After communicating with Itami Yasukiyo, Yu Qiuping finally realized the problem. No matter how difficult the iron cannon is, as long as it is aimed accurately, it is enough to hit a straight line at people. However, the trajectory of the cannonball fired from the large cylinder is a parabola rather than a straight line. The elevation angle of a large barrel shot, the amount of gunpowder to be filled, and the estimation of the distance between friend and foe cannot be practiced overnight. Yu Qiuping saw the two gunners with his own eyes, even if he practiced very hard, but the sense of distance was not good. It was about 100 meters away from Mingming, and they thought it was 60 meters. 500 meters away, they thought it was 300 meters. If they can't even estimate the distance, how can they be expected to calculate the angle of the parabola?

Only then did Yu Qiuping realize that artillery is a technical branch of the armed forces, and there are special artillery academies and universities in Europe for training. It is unrealistic to expect artillery to be as well trained as infantry and iron gunners. As a result, Yu Qiuping temporarily stopped the blind training of the gunners, and instead worked with Shigeharu Takenaka to lead a group of more intelligent staff officers to try to compile an artillery training manual.

Yu Qiuping first tried to work out a method for estimating distances – which was not easy. Because artillery requires accurate parabolic shooting, the grasp of distance must be precise. However, Yu Qiuping was also a student of systematic mathematics education, and after several days of hard thinking, he stumbled to find a way to get rid of a set of thumb ranging methods, which were very similar to the European artillery ranging methods. This method is based on trigonometric functions (or similar triangles) and measures the distance between oneself and the target by establishing two similar triangles.

The rangefinder raises one of his thumbs and uses one eye to observe a distant target of known approximate height through the upper and lower ends of the first knuckle of the thumb (e.g., the opponent's ashigaru - the height is usually about 1.55 meters, or some pre-measured trees or hills). By feeling the height ratio of the target to your thumb, and then measuring the distance between your thumb and your eye, you can calculate the approximate distance between the target and yourself.

Yu Qiuping's proposed method surprised the members of the staff and artillery crew, who never imagined that there was a way to calculate the distance step by step. They thought that if they wanted to know the length of the distance, they had to use a ruler to measure it.

However, although Yu Qiuping has come up with a method, this calculation method is too difficult for those who are not educated. None of the members of the artillery crew could learn these things. Yu Qiuping had no choice but to hold an exam for the whole family of Yu Qiu's family, trying to screen out some people with more mathematical talents to be the commander and rangefinder of the artillery crew.

To his surprise, the best test score was actually Naoe Narumu! Neither Yu Qiuping nor Naoe Tadahei noticed that this kid actually had such a good talent in mathematics. Yu Qiuping will give Yu Qiuyu, Yu Qiuyou, Yu Qiuguang, Tiger Song, and Naoe Chengyuan Pill some basic arithmetic courses on weekdays, but Naoe Chengyuanmaru's performance has never been outstanding, I don't know why he did so well in the exam this time, and he was more than ten points higher than the second place one called Senteo Onari.

However, Naoe Chenggenmaru has not yet been served, and he is only 10 years old this year, so it is still a little too early to enter the army. However, after consulting Naoe Tadahei, Naoe Tadahei was very supportive of Yu Qiuping's integration of Naoe Narumenmaru into the artillery crew. He felt that this child was so old, and it was time to experience it and make some contributions to Yuqiu's family. So, Yu Qiuping no longer shirked, and asked Naoe Narumu to be the deputy of the artillery commander Senteo Ozari. Yu Qiuping personally opened the class and taught trigonometric skills to the top 10 people in the exam.

After selecting the new members of the artillery crew, Yu Qiuping took them and began to measure the large barrel Zhuyuan. The relationship between the firing range and the amount of gunpowder, the relationship between the elevation angle and the landing point, the combination of the elevation angle, the firing range, and the amount of gunpowder refilled...... After a long period of testing, a large amount of data was measured, and after the hard work of Yu Qiuping and the members of the artillery crew calculated and summarized, a three-pounder gun training manual was finally compiled, and the training of artillery could also be on the right track. And the military industry department of Lanxiang Huadi also began to continue to produce more large cylinders to supply the troops.

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On February 13, 1572, Yu Qiuping suddenly gathered troops in the territory and sent troops to South Hanoi before the end of spring ploughing. Oda Nobunaga sent people around the time of the Chinese New Year to instruct Akihei to attack Takaya Castle before the end of spring ploughing. Because one-third of the army under Yu Qiuping is a standing soldier (that is, a soldier). However, only one-seventh or one-eighth of the troops of the Miyoshi family are standing soldiers, and the rest are led militiamen who need to participate in spring plowing and autumn harvests and will only be mobilized when the farm is slack. Yu Qiuping recruited auxiliaries to launch an attack during spring ploughing, although it would have a great impact on agriculture in the territory, but the impact on the Miyoshi family would be even greater. Such a method of self-inflicted damage of 800 and wounding the enemy of 1,000, Oda Nobunaga let his subordinates use it without any psychological burden, but Yu Qiuping had to obey the order.

The merchants in the House of Commons were very unhappy with Yu Qiuping's dispatch of troops - the use of troops during the busy agricultural season would mean that this year's harvest would be affected and the treasury would be under pressure. The lack of harvest for the common people may have reduced their purchasing power and caused problems for the merchants' shops. To make matters worse, a large number of factories opened by merchants required laborers who came only during the slack period. If Yu Qiuping sent men to start a war, many laborers would have to stay in the vacancies of the conscription on top of the territory to complete the spring ploughing of the territory, and they would no longer be able to work with them, which would have a huge impact on the factory. However, the previous constitution did not restrict Yu Qiuping's right to send troops, and at the legal level, Yu Qiuping could send troops whenever he wanted.

The House of Commons then decided to make amends and enacted a new decree: if Yu Qiuping wanted to carry out large-scale military activities during the spring ploughing and autumn harvest seasons, it must be approved by half of the parliament. The people of the Yuqiu family were furious when they heard about this bill - this parliament not only held the money bag, but now even the military command of the Yuqiu family wanted to interfere?

However, Yu Qiuping's gathering of troops during the busy farming time also offended those small wealthy clans. Although their income has nothing to do with the harvest of their territory now, it is also the land they have passed down from generation to generation. Therefore, in the upper house composed of the small wealthy clans, except for the four small wealthy families in Mino, who voted against, everyone else voted in favor of the resolution.

However, Hatakeyama stood up again at a critical moment when he pointed out that the bill of the Diet contradicted the constitutional requirement that the command of the army should be owned by the Yuaki family, declared the law unconstitutional, and ordered the House of Commons to revise it. Hatakeyama's move can be said to have saved Yu Qiuhei once, because it took a lot of time for the merchants to enact laws again. After Hatakeyama Takamasa took a stand, the small wealthy families in Hanoi also tended to follow their Hanoi guardians to stand on the same side, refusing to pass this law, putting a lot of pressure on the lower house.

At a time when there was a rift within the National Assembly, Yu Thu Binh's military campaign was carried out without restraint and launched an attack on Nam Hanoi.

The Miyoshi family was not unaware of Yu Qiuping's accumulation of troops in the territory, but they did not expect that Yu Qiuping would actually risk the impact of spring ploughing to gather the whole army to attack. Because Yu Qiuping has always been a safe and cautious person, he rarely launches decisive surprise attacks. They didn't know that this attack by Oda Nobunaga was forcibly promoted by Oda Nobunaga behind the scenes. Miyoshi Nagayi and Miyoshi Masaysu, who were located in Gaoya Castle, were caught off guard and had to gather troops together. But before they could assemble a force strong enough to rival the 2,400 soldiers of Tokiwa and Naruto, the Yuqiu army had already broken through the Yamato River defense line and besieged Takaya Castle.

At this time, the Miyoshi family had not been able to assemble all the troops in South Hanoi in Gaoya Castle, and many people had to be scattered in the small city to fight their own battles. Under the mediation of Hatakeyama Takamasa, many small Hao clans in South Hanoi, who had been suppressed by the Miyoshi Army, revolted again, and cooperated with Yu Qiuping's troops to attack the Miyoshi family's stronghold in South Hanoi. Within 10 days, the whole of Nam Hanoi had fallen under the control of Yu Thu Binh, and Gaoya Castle had become an isolated island. After the end of the autumn harvest, the Miyoshi family hurriedly assembled their troops, intending to come to to meet them. Not to be outdone, Oda Nobunaga gathered the largest army that could be mobilized by Owari, Mino, Ise and Minami Omi in Kamiraku, and prepared to fight the Miyoshi family.

Just when Yu Qiuping's South Hanoi strategy was unfolding smoothly, a big net was already being opened in secret.