Guanzhong Youfufeng is also known as Zhouyuan (original) in the oral tradition of Li Shu.
Gein is the birthplace of the Zhou Dynasty that has been passed down for nearly 800 years.
This loess plateau is sandwiched between the mountains of Longdong (Anding County) and the Qinling Mountains. It is about 50 miles deep from north to south. Although the terrain is full of ravines, the top of the table-shaped platform allows the common people to live and farm.
Livestock.
If we divide it more finely, it is the north and south of the Wei River that runs through it.
Beiyuan has a vast terrain and is rarely disturbed by flash floods, earthquakes and other disasters, so it is mostly populated by Li people. After Sima Yi became the governor of Yongliang, the Chengguo Canal opened and the military settlements and civilian fields were all located in Beiyuan.
The South Principle is much more desolate.
Originating from the relationship between the Wei River and the Qinling Mountains running eastwards, due to the influence of the continuous mountains, the terrain of the Nanyuan Plain is narrow and steep, and there is no basis for large-scale farming.
However, there are no absolutes.
For example, Wuzhangyuan is a suitable place for farming.
The Qinling Valley Road connecting Guanzhong and Hanzhong is a natural road created by water flow.
Baoxiegu is no exception.
But what makes it special is that there are two exits at the northern foot of the Qinling Mountains.
One can go directly to the mouth of Xieshui (Shitou River, also known as Wugong Water after entering Guanzhong) where Dong Zhuo built his fortress in the past, and the other can go to the mouth of Mawei River (Suiyang Xiaogu) in Chencang City. [Note 1]
The loess plateau sandwiched between these two river mouths is the Wuzhangyuan.
The abundant water source and the fan soil that was washed out by rivers can be called fertile soil, so it is not surprising that Wuzhangyuan is suitable for farming.
In fact, the Wei army did establish many camps in Wuzhangyuan.
It was not that Sima Yi was short-sighted and could not see the danger of being invaded by the Han army if he established a farm in Wuzhangyuan.
But at that time, the Han army was attacking Liangzhou. Anyone with a little strategic vision could predict that with the Han army's national strength and war background, even if it successfully occupied Liangzhou, it would not have enough power to march into Guanzhong.
Moreover, the total length of Baoxie Valley is about 350 (Han) miles.
Compared with the gain from harvesting five feet of wheat from the original farmland, the loss from mobilizing troops and marching through the valley road to send troops was greater.
It would be ridiculous if the Han army did this in a way that outweighed the gains and losses. Sima Yi didn't mind such mutual losses and was even happy to see the results.
However, this time and that time are the same.
This time, the Prime Minister made an unconventional plan and suddenly moved to occupy Wuzhangyuan, which turned out to be the enemy.
Although it is estimated that the output of the farmland in Wuzhangyuan can roughly feed 30,000 Han troops for nearly a month, it seems that it will not have a big impact on the war situation.
But in the eyes of military strategists, this is not the case.
If I eat the enemy for one minute, I will take twenty for myself.
The Han army robbed Guanzhong of grain in recent months. Calculated by the manpower and material resources required for transportation and the losses along the way, Hanzhong County was able to save ten months of grain.
In such a situation, how could Sima Yi not be heartbroken?
The reason why Sima Yi was so worried that he hurriedly rushed to supervise the troops was that Wuzhang was originally a "turf war" for military strategists.
Wuzhangyuan faces Qishan Mountain across the Wei River and is the narrowest place in the Guanzhong Plain.
If the Han army is properly deployed in Wuzhangyuan and crosses the river to occupy Qishan in Beiyuan, then the area west of Yi County will be cut off and reduced to an enclave.
And he will no longer suffer from lack of food.
If the Han army could cross the Wei River and enter Beiyuan, why would they not seize and mow all Wei's farmland there?
Therefore, when Sima Yi learned that the Prime Minister had withdrawn his camp and headed east, he immediately sent his trusted general Niu Jin to lead more than 10,000 elite troops as the front, and rushed to the Yi County area with light equipment to set up defenses to prevent the Han army from crossing the river to cut wheat in Beiyuan.
As for why they didn't rely on their superior strength and marched directly into Wuzhangyuan to compete with the Han army.
Sun Wu once said, "If you fight for land, you won't be able to attack."
The Han army entered the plateau first and took the lead in occupying the geographical advantage. A strong attack only made the Wei army passive.
This is what Sima Yi expected.
Before the troops were sent out, the prime minister decided to return to Hanzhong from Baoxie Valley and marched very quickly.
The troops were divided into three groups.
In addition to leading the army into Wuzhangyuan to seize wheat from Wei's farmland and occupy key strategic points, he also led 3,000 soldiers under the supervision of Zongyu to camp at Xiegukou to guard the way of retreat in the future. He also ordered Tiger Infantry Supervisor Meng Yan to lead more than 6,000 Tiger Infantry troops to rush forward.
We camped at the mouth of the Xie River (Wugong River) where it merged into the Wei River. In order to prevent the Wei army from crossing in from here, we cut off the connection between the Xie Valley mouth and Wuzhangyuan.
The troops are deployed in a triangular form, forming the horns of each other.
No matter where it is attacked, the other two battalions can respond and fight.
And because they are backed by the Qinling Mountains, there is no possibility of the three battalions being trapped to death, which can be regarded as minimizing the disadvantage of insufficient troops.
This kind of arrangement was familiar to both Han and Wei.
During the previous Battle of Hanzhong, the late emperor Liu Bei's tactics relied on the Ding army to form strongholds connected to each other, so as to gain the advantage of being at ease while waiting for work.
However, the strength of the Han army was still too small after all.
The prime minister, who only led 30,000 soldiers into Guanzhong this time, could no longer dedicate troops and horses to stay at the mouth of the Mawei River to prevent the Wei army from entering the Baoxie Valley from the Suiyang Valley and occupy the small flat land in the middle (today's Taibai County), cutting off the Han army's return route.
possible.
But the prime minister felt that the Wei army would never send troops into Suiyang Xiaogu.
It's not that he was fooling Sima Yi because he couldn't even see such an obvious omission.
Instead, he concluded that he did not dare.
Because this omission was not only a flaw in the Han army's deployment, but also a trap hiding murderous intent.
The southern section of Baoxie Valley has always been under the control of Hanzhong County. If the Wei army dared to go deep into the Suiyang Valley, they would face a situation where the Prime Minister and Wu Yi would attack from the north and south.
Fighting in the plains, the Wei army's combat power was still weaker than that of the Han army.
Does Sima Yian dare to send troops into the rugged valleys to compete with the Han army, which is best at mountain warfare?
If he planned it like this, it would be truly foolhardy!
Naturally, Sima Yi is not a fool.
As he led the army behind him, he received military information from the scouts along the way. After learning about the deployment of the Han army's troops, he did not even bother to stop at the mouth of the Mawei River.
But the marching speed slowed down a bit.
Niu Jin, who had already rushed to the front of Beiyuan to set up defenses, sent his men back to report back. The Han army had no intention of crossing the river to seize the wheat in the field, and they did not even build a pontoon bridge to prepare for a fierce battle.
This puzzled him.
Is it possible that Zhuge Liang, the Prime Minister of Shu, transferred his army to this area just to seize some farmland in Wuzhangyuan?
To spend more than one month in Guanzhong?
This inference was quickly dismissed by Sima Yi.
He didn't think the Prime Minister's intentions would be simple.
Even if there is no better reason to explain why the Han army went on the defensive.
Because Wuzhangyuan was about three hundred miles away from Chang'an City, even if the Han army wanted to go eastward, it would not be able to march in a concealed manner.
In fact, he had roughly guessed the prime minister's intention.
The biggest reason why the Prime Minister transferred his army to Wuzhangyuan was to delay the main force of Wei State in Guanzhong for a little longer, so that the Wei Yan tribe in Hexi could act with less worries.
Another thought was to follow the trend and take the opportunity to familiarize the soldiers with the topography and geography of Guanzhong.
Know yourself and know the enemy.
Sooner or later, the Han Dynasty will launch a battle to restore Guanzhong and return the old capital, so Quan should prepare in advance.
Naturally, if the Wei army came to attack, the prime minister would not miss the opportunity to test Sima Yi's command.
Compared with the previous Cao Zhen, Sima Yi seems to be more stoic. He has been appointed as the governor of Wei Yongliang for more than two years, and has never led an army to fight against the Han army!
The Prime Minister is looking forward to a fierce battle with Sima Yi.
The strength of the Han army's military strength will prevent them from easily starting a war in the future, giving the Han army time to recuperate.
[Note 1: Today the northern section of Baoxie Valley is National Highway 244, and the small valley of Suiyang is National Highway 342. Those who are interested can go to pay homage to the road used by the Prime Minister’s last northern expedition]
