Because the geographical works before the Book of Continued Han did not record the mileage of counties and capitals in detail, the earliest records we can see today are the Book of Continued Han written by Sima Biao, a historian of the Western Jin Dynasty, and the Book of Later Han written by Ye Fan of Nanliang. In addition, the Historical Records of Huayang, written by Shijiachangqu in the Eastern Jin Dynasty, records the historical and geographical evolution of Nanchuan, Shaanxi, Hubei and Yunnan areas in the Qinling Mountains, and is later than the historical records of counties and counties in the Han Dynasty, with high mileage accuracy and is an important reference material.

First, the distance between counties recorded in historical records.

Later Han Dynasty: Five Records of Twenty-three Counties

Qin family in Hanzhong county. Luoyang is 990 miles to the west.

Wudu County, the hometown of Emperor Wu of Han Dynasty. Luoyang is in the west 1960 miles.

Gaudi home in Guanghan county. Luoyang is three thousand miles west.

Qin family in Shu county. Luoyang is 3 100 miles west.

The History of Qin Dynasty Jing Zhaoyin was revised by Liang Wudi. Its four counties belong to Jianwu fifteen years. It's 950 miles west of Luoyang.

Huayang National Records Volume II Hanzhong Records

Zitong County, ... Go to Luo 2838 Li.

This Wudu county in the west of Guanghan is also ruled by a captain ... Go to Los Angeles 1878 miles.

Yin Pingjun, a captain in the north of Guanghan [rule] ... go to Luo 2344 Li.

Records of Huayang Country Volume III Records of Shu

Shuxian, ... 3 120 miles to Los Angeles.

Guanghan County, ... 3000 Li to Los Angeles, 0/20 Li to Chengdu/KLOC.

It can be seen from the records that the distance from Hanzhong County (Nanzheng, now Hanzhong City) to Jing Zhaoyin (Chang 'an, now northwest of Xi 'an) is110 Li Han; Zitong County Governance (now Zitong, Sichuan) Distance Jing 1888. The distance from the military administration of Shu Army (now Chengdu, Sichuan) to Jing Zhaoyin is 2 150 ~ 2 170 Li Han. The distance from Yin Ping County (now Wenxian County, Gansu Province) to Chang 'an is 1394 Li Han.

Second, the corresponding urban distance of modern transportation

1. Look at the traffic between Hanzhong and Chang 'an first.

During the Han, Three Kingdoms and Jin Dynasties, the traffic between Hanzhong and Chang 'an was mainly connected by ramps and ancient roads. Thanks to the highway, the total length is 256.5 kilometers along the provincial highway 2 10 from Liuba Meixian to Wuguanyi Town and the national highway 3 16 from Wuguanyi Town to Hanzhong City. The distance from Meixian to Xi 'an along the 3 10 national highway is135km. In this way, it is 94 1.6 Li Han (1 Li Han is 0.83 16 Li, 0.4 158km in this city) along Xi 'an-Hanzhong 39/kloc-0 .5 km. See Research on the Length Evolution of China, Li Yang and Research on China's Economic History. This distance is shorter than that calculated in the Book of Continued Han Dynasty, so it can be seen that although this route is not the main road of the later Han Dynasty, it is indeed more convenient.

There is no objection to this old road from Baoji to Fengxian in history, mainly from Baoji to Fengxian along baoji-chengdu railway. Today, Baoji to Xi 'an is along 3 10 national highway 197 km, baoji-chengdu railway Baoji to Fengzhou 9 1 km, and Fengzhou Town to Fengxian is along 2 12 provincial highway 16 km. The main argument is whether to continue to pass through the Jialing River or other roads when entering Hanzhong, which is south of Fengxian County. There are four main arguments:

First, from Fengxian to the southeast, through Tianxing Town, Liu Hou Town and Wuguanyi Town of Liuba County (that is, the plank road in Li Anyun), south into Hanzhong. However, this road, known as "Li Anyun plank road", was obviously opened by the Northern Wei Dynasty, but it did not exist in the Qin and Han Dynasties, so it was not considered.

Second, from Fengxian along the Jialing River to the south of Lueyang, turn southwest through Hejiayan Town and Heihe Dam Township, and pass through Chadian Town (Han County), Wuhou Town (Guyang Guanping) and Mianxian County (Hanyang) along the giant water to Hanzhong. The distance from Baoji to Lueyang in baoji-chengdu railway is 2 15km, and the mileage from Lueyang to Hanzhong along provincial highway 309 is 1 16km. If you take this route, the distance from Xi 'an to Hanzhong is 528km, which is 1270 Li Han.

Third, from Fengxian along Jialing River to the south of Lueyang, turn southwest through Guanting Town (Gufei County Ridge), along Dalin River (Guchen Pingshui) north of Hanjiang River, through Miaoba Township to Da 'an Town (Jinniu County in Tang Dynasty), and then eastward to Hanzhong. The distance from Baoji to Lueyang in baoji-chengdu railway is 2 15km, from Lueyang to Daan Town along the highway is 52km, and from Daan to Hanzhong along the 108 national highway is 88km. Then the route from Lueyang to Hanzhong is 140 km. If you take this route, the distance from Xi 'an to Hanzhong is 552km, which is 1329 Li Han.

Fourth, from Lueyang along Jialing River to Ningqiang Yangpingguan Town, then turn to the northeast, and pass through Daijiaba, Daan, Qingyangyi, Wuhou Town and Mianxian County to Hanzhong. The distance from Baoji to Yangpingguan in baoji-chengdu railway is 27 1 km, and the mileage from Yangpingguan town to Hanzhong along the highway and 108 national highway is 1 17 km. . If you take this route, the distance from Xi 'an to Hanzhong is 585 kilometers, which is 1407 Li Han.

It is not difficult to see that the route through the tea shop-Wuhou Town seems to be more in line with historical records.

2. Look at the traffic between Chengdu and Chang 'an.

Because the journey from Zhao Hua Town in Guangyuan to the south and around Langzhong and Langxian along Jialing River is much farther than Shi Niu Road. Baoji-chengdu railway Guangyuan South Section is different from Shi Niu Road in history, and does not pass through Zitong, so the national highway 108 route is adopted for calculation. In addition, the following route of Zitong, Shi Niu Road is unique. We can infer the traffic route from Chengdu to Chang 'an by verifying the distance from Zitong to Chang 'an.

When studying the distance from Zitong to Chang 'an, the first question is whether Zitong to Chang 'an must pass through Hanzhong. Let's look at it separately.

First, if you need to pass Hanzhong from Zitong to Chang 'an, the distance from Zitong to Hanzhong is 778 Li Han. It is divided into three situations:

A. From Hanzhong to Zitong via Da 'an, Guangyuan, ningqiang county, Sichuan, that is, along the national highway 108. The distance is 374 kilometers, or 899.5 Han Li.

B. From Hanzhong via Da 'an and Yangpingguan towns, south along Jialing River to Guangyuan, and then along National Highway 108. The distance from Hanzhong to Yangpingguan Town is 108 national highway and highway10/7km, the distance from Yangpingguan Town to Guangyuan along baoji-chengdu railway is 79 km, and the distance from Guangyuan to Zitong, Sichuan is 157 km. If you take this route, the distance from Hanzhong to Zitong is 353 kilometers, which is 849 Li Han.

C. From Hanzhong, it passes through Da 'an, Yangpingguan, Yanzibian, Guangping and Shazhou towns in Qingchuan, Sichuan (Baishui in Han Dynasty), then it goes southwest along Bailong River, reaches Zhao Hua Town in Guangyuan (Hanjiameng and Three Kingdoms Hanshou) and then goes south to Zitong. Hanzhong is 203km away from Shazhou Town via National Highway 108, 20km away from Shazhou12 along National Highway to Baolun Town in Guangyuan (Baolun Town is 25km away from Guangyuan). Distance from Baolun Town to Zitong 108 National Road132km. The cement road from southeast of Baolun Town to Zhao Hua Town is 2 1 km long. The distance from Baolun Town to Jianmen Town along 108 National Road is similar to that along cement road via Zhao Hua. Therefore, we take the 108 national highway from Baolun Town to Jianmen Town instead of the cement road from Zhao Hua to Jianmen Town. If you take this route, the distance from Hanzhong to Zitong is 455 kilometers, which is 1094 Li Han.

It is not difficult to see that the most historic route from Zitong via Hanzhong to Chang 'an is the route from Yangpingguan Town to Guangyuan Zhao Hua, which is only 6 1 Li Han, about 25 kilometers.

Second, if Zitong goes to Chang 'an without passing through Hanzhong, the situation will be more complicated.

First of all, there are two routes to the south of Yangpingguan Town, one is from Yanzibian Town to Guangyuan, and the other is through Shazhou Town in Qingchuan.

A. The route from Yanzibian Town to Guangyuan directly. The distance from baoji-chengdu railway Yangpingguan Town to Guangyuan is 79 kilometers, and the national highway 108 Guangyuan and Zitong mileage 157 kilometers. Then along this route, the distance from Yangpingguan Town to Zitong is 236 kilometers.

B. the route through shazhou town, Qingchuan. The mileage from Yangpingguan Town to Shazhou in Sichuan is 86 kilometers. As mentioned earlier, the distance from Shazhou along the 2 12 National Road to Guangyuan Baolun Town is120km. Guangyuan is 25km away from Baolun Town, and Baolun Town is 32km away from Zitong 108 National Road. Then along this route, the distance from Yangpingguan Town to Zitong is 338 kilometers.

Secondly, there are three lines to the east of Yangpingguan Town, namely Jialing River Line, Chenpingshui Line and Chadian-Wuhou Town Line mentioned above.

A. the distance from Baoji, baoji-chengdu railway to yangpingguan town on Jialing river line is 27 1km, so the distance from yangpingguan town to Chang' an on this line is 468km.

B. Chenpingshui Line is 29 kilometers from Yangpingguan Town to Da 'an Town, 52 kilometers from Da 'an Town to Lueyang Road, and 2 15 kilometers from Lueyang to Baoji baoji-chengdu railway, so the distance from Yangpingguan Town to Chang 'an is 493 kilometers.

C. The Chadian-Wuhou Town line is 29 kilometers from Yangpingguan Town to Da 'an Town, 36 kilometers from Daan Town to Wuhou Town along National Highway 108, 64 kilometers from Wuhou Town to Lueyang along Provincial Highway 309, and 2 15 kilometers from Lueyang to Baoji baoji-chengdu railway, so the distance of this line from Yangpingguan Town to Chang 'an is 54 1 km.

Then, we add the pairwise combination of the north and south lines, and get the distance from Chang 'an to Zitong on different lines: AA-704 kilometers, which is 1693 Li Han; AB-729 km, namely 1753 Han Li; AC-777 km, namely 1869 Li Han; Ba-806 km, 1938 Li Han; BB-83 1 km, or 1999 Han Li; 879 kilometers BC, 2 1 13 Li Han.

It is not difficult to see that the route from Zitong to Chang 'an passes through Guangyuan, Jialing River in Yangpingguan Town and Chadian to Wuhou Town, and passes through Qingchuan Shazhou (Baishui County in Han Dynasty) and Jialing River in Yangpingguan and Lueyang, which is close to historical records. However, considering a section of Jialing River in Yangpingguan Town, Lueyang, it is difficult to travel. The latter seems to be a route that conforms to historical records.

Mr. Li compared Jialing River Line with Chadian-Wuhou Town Line (referred to as the "Western Line" in this paper) in the article Tracing Back-On the Special Position of the Old Road in Sichuan-Shaanxi Postal Road (Northwest History and Geography Research, Zhongzhou Ancient Books Publishing House, 1994). According to Yuanhe County Records, the distance from Lizhou to Chengdu is 760 Li, and it will continue. Then the route from Chang 'an to Chengdu is 2 140 Li. It is very close to the 2 150-2 170 Li Han recorded in Hanshu and Huayang Guozhi. But in the Tang Dynasty, the south of Yangpingguan entered Shu, and it had already embarked on the route of Jialing River passing through Guangyuan. If we subtract 282 Li between Chengdu Zitong from 2 140 of this route (including Li Tang system), the distance between Chang 'an Zitong on this route is 1858 Li. It is about 100 miles from the AB line we got above.