Efficacy of the Great Wall

heylouis

Ad Honorem
Apr 2013
6,612
China
I wud call it a sort of safety engineering. Or security engineering, if you like.

It's kind of like spending time to build a security system around your home, to keep the burglars at bay. The time & resources expended for it wud impact on the yield & productivity of your farm, if you're a farmer.

But the loss to your farm wud only be a temporary one, and you wud be able to recompense for it, e.g. by working harder & longer, or using extra workers, the following week or month.

But the system protecting your home just has to be done. It is for the long term.
not exactly like this....

the human society is complex and not rational.
 
Jan 2016
611
United States, MO
@heylouis
That's why mathematics is important, because I remember strongly that the Qin estimated the number of peasants needed to build a number of lengths for specific durations, I just don't know how to find the source, if anyone can confirm, I'd be grateful.
The only thing in the Shiji that mentions the great wall is a couple lines.

秦已并天下,乃使蒙恬将三十万众北逐戎狄,收河南。筑长城,因地形,用制险塞,起临洮,至辽东,延袤万余里,于是渡河,据阳山,逶蛇而北。

After Emperor Qin took all under heaven, he sent General Meng Tian with 300,000 troops north to RongDi and took the land south of the river. They built the great wall following the terrain and using strategic passes. It started from Lintao and went to Liaodong, stretching over 10,000 li, then it crossed the river, and snaked north by the Yang mountain.

My translation likely has a few issues, and there may be some other writing about the Qin's wall building in the Book of Han. The problem is that these figures can't really be relied on. The number of troops seems high and the distance is very vague. I highly doubt Sima Qian went there to measure the length of the wall in any case.
 
Jan 2018
1,609
China (Hong Kong SAR)
@The Keen Edge
Measuring distance is not doubtful, building such a long wall is doubtful, but that was done so measuring the distance really shouldn't be a problem at all.

Han Dynasty horse-drawn odometer:
 
Jan 2016
611
United States, MO
@The Keen Edge
Measuring distance is not doubtful, building such a long wall is doubtful, but that was done so measuring the distance really shouldn't be a problem at all.

Han Dynasty horse-drawn odometer:
Thanks for letting me know about that. Still not sure how it works though, does the thing on top spin with the turning of the wheels or something?
 

sparky

Ad Honorem
Jan 2017
5,338
Sydney
.
there is a story told about the Western Gate of the Wall , I don't know if it is true but it's a good one

the Imperial court decided to build a castle at the end of the wall at Jiayuguan
a famous architect was asked to provide the plans and material list for the building
he gave the bricks quantity down to the exact number needed
the imperial administration told him to get real , the place was at the end of the world , whole caravans disapeared in the sand storms , he was told to provide a safety margin.
he returned his estimate ...plus one brick .

When the castle was finished , there was one brick left which was placed on top of the main gate
 
Dec 2010
183
The early Great Walls, being only around 2 meters tall, was never meant to be a defense against serious intrusions, but merely against small intensity raids. It could literally be taken apart by shovels within hours. This wall was not merely defensive, but could be used as a forward demarcation line. The Han had two lines of Great Wall, one on the borders of Chinese settlements, extending into the Ordos and the second way further north in the Gobi desert, extending into present day Mongolia itself. The Ming walls are the true defensive walls, and was the most grandeur of the walls and what we see today. Only three dynasties since the Qin never conducted large wall building projects, and these are the Tang, Yuan and Qing, because of their control of the steppe or cordial relations with nomads.
The Tang, Yuan and Qing were all more or less of nomadic/ semi-barbarian origins. That would explain how they projected their power there: by actively invading/ raiding the enemies.
Not many people know that tidbit about the Tang dynasty.
 

heavenlykaghan

Ad Honorem
Mar 2012
4,486
The Tang, Yuan and Qing were all more or less of nomadic/ semi-barbarian origins. That would explain how they projected their power there: by actively invading/ raiding the enemies.
Not many people know that tidbit about the Tang dynasty.
I doubt the nomadic origins had much to do with it; since the Sui is likewise of the same Guanlong aristocratic background as the Tang and it still built a lot of walls. Plenty of non-native originated northern regimes also built walls, the Northern Wei, the Jin and Xixia all did. The Tang founders were also not nomadic even if they were inter-married with the Xianbei aristocrats. The Tang conquest of the Turuks and the subsequent establishment of large military garrisons and military commissioners, along with cordial relationship it established with the second Turuks and Uighur meant the Tang did not look to built walls.