How many pigs were there in China during the warlord era?
I came across the wonderful site Strange Maps, and one of their offerings was a 1922 map of world hog production
The text says that this is a map of industrial-scale pig breeding. China seems a bit over-represented here. Yes, every farm in China should have a couple pigs. So should every farm in Ohio and Korea, but the densities there seem much lower, and it can’t just be population. Were Chinese really eating all that much 
? Or was there a big export industry? Either would be interesting as the first would be a sign of a surprising prosperity, and the later a sign of China getting an export industry right in the 1920s. Does anyone know if there is anything out there on Late Imperial/Republican pigs?
What qualifies as “industrial scale” pig farming? If it was just pig population, that is one thing, but I cannot imagine too many industrial scale places in 1922 China.
General Yan,
“industrial” was the word used in the original source, an American reference work. I’m pretty sure there were not many North Carolina style hog farms in China in 1922. On the other hand China did produce large quantities of eggs and bean cake and stuff like that for export, so there may have been that many pigs. I suspect something is happening here, but I don’t know what it is.
There is a fascinating article on the role of pigs in Ding Xian, a county in North China, with references to further sources: Sigrid Schmalzer, “Breeding a Better China: Pigs, Practices, and Place in a Chinese County, 1929-1937,” The Geographical Review 92.1 (January 2002): 1-22.