The situation in Yizhou is really very bad.

Although there are many states in the world, but the terrain is such a relatively closed area as Yizhou can only be compared with Jiaozhou, and there are many mountains in its state, plus several checkpoints, that is, Sizhou, which is blocked by the Yellow River, Qinling, Plateau, and Tongguan, is far from being comparable - how flat is Sizhou!

It is never the general's talent that governs the war, but the time and place, and the talent of the people is nothing more than the advantage of the situation. A good general can choose tactics and strategies according to the pace of the battle according to the inherent time, place, and people.

The pace of battle is fast, the interval is short, and the emphasis on tactics is more and more strategic; On the contrary, the strategy occupies a greater proportion of the importance.

The topography of Yizhou determines that the strategy occupies a dominant position here.

The difficulty of the road in Yizhou is two-way, not only affecting the march of Yan's soldiers and horses, but also affecting Liu Bei's troops, which brings huge pressure to the march and baggage of the armies of both sides.

Ma Chao spent two full months besieging Baishui Pass, not because he didn't have the ability to force through Baishui Pass, if he wanted to, the stone cannons sent from Hanzhong could smash the pass to the ground in three days...... Or use a boulder to smash a path outside the pass that can be rushed.

But he didn't, because he discovered a very sad fact - when the tug-of-war was at Whitewater, he had the advantage.

In other words, the farther the battle is from Chengdu, the greater his advantage, if Guan Yu dares to lead troops into Hanzhong, then this bearded man who makes King Zhao unforgettable will die!

Because of the baggage, Yan's advantage in transporting the baggage is much greater than Liu Bei's!

Most of Zhang Lu's subordinates were from Yizhou, and they knew how far it was from Chengdu to Baishuiguan, and people could not say the exact number, but the distance was about 1,800 miles. This distance, placed in the north, is nothing more than Handan City to Zhongshan, galloping horses and horsemen can be reached for two days without stopping, that is, the donkey cart will arrive in five days. But in Yizhou? It's impossible to come over after half a month on horseback. Of course, relying on two legs, it will only take twenty days to get used to walking.

Because you have to climb the mountain.

There are Baishui Castle and Zitong, Fuxian, Mianzhu and other places along the Baishuiguan, but these cities without exception have the ability to supply the grain and grass needed by the army. Only Chengdu, only Chengdu Prefecture, has the ability to mobilize military rations and baggage from the state to deliver them to Baishuiguan.

If Liu Beijun's baggage line wants to be sent to Baishui Pass, there are two roads. The land route is like the cities along the above, from Mianzhu, Fuxian, Zitong all the way to Baishui City, over two big waters, over more than a dozen mountains, the road is thousands of miles, even if it is urgent, it is not possible to reach it in 15 days; By land and water, take a boat from Chengdu to the southeast through Zizhong, Han'an to Jiangyang, transfer northeast from Jiangyang to Ba County, take the Han River through Jiangzhou, Anhan, Chongguo, Pujia and other eight counties, travel 1,700 miles of water and land, can be sent to Baishuiguan.

Half of the journey was long, and the time ranged from five to twenty-five days, and the speed of the boat on the waterway was not stable, and the date of arrival was different against the current, against the wind, and with the final date of arrival.

But Liu Bei didn't have a choice, firstly, there was less food and grass on the waterway, and secondly, it was also the most important thing, he could transport horses by boat. Although the general environment of Yizhou is uneven, it is not difficult to find a piece of land that can be used as a horse war, not to mention that once he attacks Hanzhong, which is much flatter, and fights against the Yan army with many horses and knights, Guan Yu will suffer a big loss.

As for whether Yanbei would use his world-leading cavalry in Han, Liu Bei thought that there was no need to think about it at all...... All the good horses in the world are in the hands of the Yan family, but Liu Bei, who is also from Youzhou, has fallen to the point where he is now lacking horses like the southern princes.

Therefore, Liu Bei used both roads, transporting a small amount of grain by land, and Minzhuang was armed to deliver continued supplies to the northern army; Land and water transported a large amount of grain and his only war horses, hoping to support Guan Yu at a later time.

The advantage of this place in Yizhou is that it is closed, and the disadvantage is also closed, Ma Chao has never lived in Yizhou, but he already knows where Liu Beijun's grain road is...... There are only these two major roads in Yizhou, and Liu Bei has not many choices at all. However, even if Ma Chao knew, it would be useless, because the road in Yizhou is not like other places in the world that can be bypassed if you want to.

Thorns can be split, and mountains and seas can be moved by manpower?

What kind of surprise attack, food shortage, extinction, and harassment of the Liangzhou army's specialty cannot be used here at all, but it is the wave war and hard war often used by the Jizhou people in the early years to win the battle to make meritorious contributions - as for who the Jizhou people are talking about, of course, it is the Yellow Turban Army represented by Zhang Jiao, Zhang Yan and others.

However, this is not to say that Yizhou's geographical advantages really make it impossible to use tactics, such as ambushes and damming rivers, which are very useful means.

Zhao Yunbu went out from the east of Wudu County, Liangzhou, and walked the Yinping Road of the Guanghan Subordinate State, located on the east side of Baishui Pass, and turned sharply down along Baishui, in the upper reaches of Baishui Pass, Zhao Yun left several capable officials brought out by Liangzhou, and for two months they were there to command Ma Chao to send people to recruit soldiers from the Qiangdi tribe to barrage the river and build a dam; Zhang Lu also led people to dig the river on the west side of Baishui Pass, but with little success.

Zhang Tianshi was frightened by Guan Yu.

The general guarding Baishui Pass is naturally Guan Yu, and there are also some elite soldiers and strong generals under his command, such as Huang Zhong, Wei Yan and others, who are more fierce than the other, and they have the style of Liu Bei's old revolution.

Zhang Lu dug a river on the other side of Baishui in the west dozens of miles away from Baishui Pass, but in two months, Guan Yu led the army to quietly cross the river at night and attacked three times. Even if Ma Chao is only stationed a hundred miles away, when the main reinforcements arrive and Guan Yu returns to the pass early, where can he still find a trace of him.

However, this is not to say that Ma Chao has no military exploits in the two months of encircling Guan Yu here, Baishui Pass is not insurmountable because of this white water, Ma Dai took advantage of this river to lead dozens of small boats to force the south, and intercepted a baggage fleet from Chengdu at the river near Pujia, and sank the baggage that Liu Bei had worked so hard to send, and the ones that could not be taken away, burned and burned to the bottom, and did not send Guan Yu at all.

In Ma Dai's heart, this waterway is really weird, both sides are full of mountains and cliffs, except for those who have no square inch to land along the Baishui Pass, continue to the south to approach Pujia, Ma Dai is worried about being discovered by the enemy in the city, and only sends a few sailors to the shore to take a look at the place far away from the city, and then goes upstream, and returns to the camp outside the gate at night a few days later.

Ma Dai clenched his fists and said to Ma Chao: "Brother, it is difficult to cross the white water, if you don't rush to break the city, otherwise the guards will only need to cut off the waterway to block our army." However, before the general attack, the garrison in the city is empty, so we can grab the Pujia first and trap Baishui from the water and land! ”