In March of the seventh year of Xingqian, when the spring breeze returned to the south bank of the Green River, when the ice on the Huai River began to melt, the willow branches on the bank of the Huai River were tender. When the women of Zhongdu were planning a place to go with their families on Saturday, no one noticed that this spring event was brewing.

On March 12, on this day, the Governor's Mansion of the Five Armies, the highest military command department of the Ming Dynasty, was on the same high guard as before, and the carriages drove into the Governor's Mansion, if anyone paid attention, they would definitely be able to notice the sentries outside the Governor's Mansion, which were a little more than in the past, and those sentries watched the passers-by on the road vigilantly, and in the courtyard of the Governor's Mansion, the sentries with military dogs were patrolling back and forth to prevent anyone from entering.

Although it is well known that the Governor's Mansion of the Five Armies has always been heavily guarded, it is the first time that he has looked like a great enemy.

Outside is heavily guarded, and around the large combat map room in the Governor's Mansion of the Five Armies, there are three steps and one sentry, five steps and one post, only some hurried generals walk into the combat map room with expressionless faces, and then the thickest soundproof wooden door will be closed again.

This is not the first time Li Dingguo has come to the operational map room of the Governor's Mansion of the Five Armies, but this is the first time he has seen such a large giant sand table, after handing over the military power to the central capital, Li Dingguo was amazed by the exquisite sand table of the military department, although he also built a large terrain sand table in Guangzhou in the past, but those sand tables can not be compared with the military department.

In addition to using colors to represent roads, rivers, villages and forests, the sand table model of the military department not only has mountains, hills, cities, etc., but also reflects mountains, water bodies, roads and other objects in the model, and the scale standard, in addition to using colors to represent roads, rivers, villages and forests, it will also use porcelain blocks and flags with signs to represent the army and weapons, so that the audience can understand the terrain through the sand table more macrocoscopically. Carry out strategic planning according to the actual combat method. And this kind of "war game" is called sand table work in military schools, and it is also the most important deduction of the Ming army.

And its inventor is none other than His Majesty the Emperor, in the Imperial Palace, His Majesty will use a sand table for military games. It is said that His Majesty once conducted a battle with the crown prince and the prince on a scale of hundreds of thousands.

Of course, it's not just the royal family, in fact, most of the noble families of the Ming Dynasty will have several sand tables, and those nobles with military positions will teach their sons how to command, how to dispatch, and how to fight on the sand table. This is also the reason why most of the children of those nobles excel in their studies in the army school - when the children of civilians are still studying in social studies, they have already begun to learn how to command troops in battle, and even master the skills of training soldiers at home by training servants. And their fathers are often experienced soldiers, and will tell them about their lifelong experience, this kind of family education inheritance is difficult for ordinary families to achieve.

Thinking of this, Li Dingguo looked at the staff officers with crossed copper bamboo knots on the collar badges on the side, many of the young staff officers were the sons of some nobles, and they were all so-called sons.

Now they all stood there with solemn expressions, and they didn't even dare to come out. Not because the emperor is here, but because here, no one dares to make a mistake.

“…… In addition to the 30,000 defenders of Tongguan, the strength of the slaves in Xi'an does not exceed 20,000, and the other 30,000 people are scattered in Shaanxi, especially in the passes, and the main force of about 130,000 slaves has moved to the Western Regions with their families as early as last year, and the defensive strength of the slaves is so large, and in the passes, although the strength of the slaves is limited, they have built fortresses with the passes in the past few years, and the terrain is easy to defend and difficult to attack, so the western expedition should take Tongguan as the main battlefield......"

Expedition to the West!

This was the center of the discussion at this combat meeting, when Yu Shujie, the chief of staff of the Ming Army, pointed to the Tongguan Pass on the sand table with a wooden pole, Zhu Mingzhong's eyes were fixed on the other passes leading to Shaanxi, and it could be seen from the appearance that those passes had all been improved without exception - European-style fortresses towered over the passes.

Because the location of those fortresses is easy to defend and difficult to defend, and the fortresses are built on the mountain, even if he does not visit the site in person, Zhu Mingzhong can imagine how dangerous those areas are.

If they made a mistake, when the Qing army built the fortress, they should have been stopped by some means. Thinking like this in his heart, Zhu Mingzhong stared at Tongguan again, and then asked rhetorically.

"So, how do you plan to capture Tongguan?"

"Back to Your Majesty, to capture Tongguan, you can take the excavation to attack the city, according to the information we have in the past few years, at present we have preliminarily selected three positions, with the cooperation of the attacking troops, the sappers can dig to the bottom of the city wall within two weeks, and then destroy the city wall through blasting......"

Explosion and trapping the city, for the Ming army, can be said to have been lightly familiar with the road, and it can even be said that the Ming sappers are good at playing, although during the Northern Expedition, there were no blasts at all a few cities, but in the training of sappers, excavation and explosion operations are a compulsory course for sappers, and because of this, this will become the first choice of the General Staff,

However, Yu Shujie still noticed that His Majesty's brows were slightly locked, and he seemed to be a little dissatisfied with the blasting siege, so he came up with an alternative plan.

"Of course, the use of excavation and blasting to capture Tongguan, it takes at least half a month, so in addition, there is an alternative, is to use large-caliber mortar artillery to attack the city, as early as six years ago, in order to capture Tongguan, the Governor's Office of the Fifth Army ordered the arsenal to study large-caliber mortar for siege, three years ago, the 15-inch mortar was successfully developed, he can smash more than 200 pounds of shells on the city wall from 4 miles away, according to our calculations, concentrate 48 15-inch mortar guns, can destroy the Tongguan city wall in three days......"

"Three days ......"

Raising his head to look at Yu Shujie, Zhu Mingzhong asked rhetorically.

"Since this time is shorter, why is this method not the first choice?"

One is half a month, the other is three days, and the soldiers are fast, which is the least truth.

"Your Majesty, because the 15-inch mortar cannons are too heavy, each weighing nearly 15 tons, and most of those mortars are now deployed in coastal batteries, it will take at least a few months to mobilize 48 mortars, so the Governor's Office of the Five Armies is more inclined to use blasting operations."

It's coming, Yu Shujie specially added.

"The 15-inch mortar gun was developed in the name of the coastal mortar gun, so after being equipped, the coastal battery was the mainstay, and the army was only equipped with 12 ......"

The seeming explanation made Zhu Mingzhong's heart sigh helplessly, bureaucracy is everywhere, even in the 17th century, it was inevitable, it was clear that the project was for siege, but in the end the equipment was given to the navy, and it was even sent to the batteries that did not need it, and the army that needed it could not get a sufficient number of artillery.

Even as an emperor, even if he knew all kinds of problems, Zhu Mingzhong could only pretend to be confused, just nodded slightly, and then said.

"Oh, so if we mobilize more 10-inch guns, can we make up for it in terms of numbers?"

The answer, of course, is yes.

Daming has a sufficient number of mortars, although the caliber is different, but not only 15 inches, but also 10 inches and other calibers of other caliber mortars, these artillery was originally developed for the siege of the city, when the bombardment of Shenyang, although the mortar played a great role in destroying the buildings in Shenyang, but the real Shenyang city of the enemy's resistance will to blow up the ashes, it is such as ten inches and other heavy mortars.

It's a pity that there are no real siege artillery!

Thinking of another time and space, the 280 mm coastal mortar guns used by the Japanese army in the attack on Lushun, the rifled mortar cannons were extremely powerful, even able to penetrate several feet of reinforced concrete, and the accuracy was quite high, in this era, the same siege city, but only with shells to "smash" the city wall.

However, this should also be the last fortified city, once the Tongguan is torn open, the entire Guanzhong Plain is like the Ming Dynasty open, and the hundreds of thousands of troops of the Western Expedition can drive straight in, along the Tongguan all the way to Xi'an, and then continue to the west......

In the hours that followed, the generals, including Yu Shujie. constantly explained the specific details of the Western Expedition, and Zhu Mingzhong would ask some questions from time to time, that is, some of the details of the problems, which seemed to be very simple, but they were also extremely important.

Zhu Mingzhong was also quite satisfied with the answer given by the Governor's Office, after all, this was a perfect battle plan that took almost seven years, and in order to complete this plan, in the past six years, hundreds of troops were collecting military intelligence in Shaanxi, and those young staff officers even entered Shaanxi in their personal capacity for staff trips, inspecting the environment in various places on the spot, and preparing for the westward expedition.

This is the most well-prepared battle in the history of the Ming Dynasty, and this sufficiency is not only in terms of intelligence, but also includes personnel and materials.

“…… After the first batch of troops seized Xi'an, the second batch of troops, also 70,000 troops, will enter Tongguan in turn, and when they seize Xi'an, they will take over the main attack task, and the first batch of troops will be responsible for the rearguard, and carry out rest, at the same time, the reserve in Henan will attack Shaanxi when the second batch of troops leave Xi'an, and take over the first batch of troops, and so on, and so on, each batch of troops can get a full rest, so as to avoid a decline in combat effectiveness due to the exhaustion of officers and soldiers......

Because warfare in this era relied entirely on manpower and animal power, it was necessary to ensure that the troops could be fully rested, which is why although the westward expedition ostensibly involved as many as 270,000 troops—almost two-thirds of the country's troops—in reality, only 70,000 to 80,000 troops were used for the offensive.

Later, after explaining the logistics support issue again, his eyes stared at the sand table, Zhu Mingzhong pondered for a moment and then asked.

"When is the time for the attack?"