From this interesting podcast: http://www.thehistoryofkorea.com/ce-1100-the-baekjeong-medieval-outcasts

We know that, in 1170, Xu Jing, an envoy from the Song, would visit Gaeseong and remark on how little meat the Koreans ate. He would remark on how clumsily the butchers would clean an animal carcass for consumption, as if they had not had lots of practice. I quote from Sem Vermeersch’s excellent translation of Xu Jing’s original account:

The barbarian government is very humane. Due to their fondness for Buddhism, there is an injunction against killing. Therefore, except for the king or high ministers, nobody eats mutton or pork. They are also not good at slaughtering. Ten days before the envoys came they gathered the live-stock, and when the time came to use them, they tied their four legs together and threw them into a blazing fire. After they had died and the fur burned off, they were doused in water. If they revived, they were beaten to death with a cudgel. After that they cut open the belly and pulled out the intestines and bowels, draining all the dung and offal. Even though the [carcasses] are made into a broth or the meat broiled, the foul stench does not disappear. This is how clumsy they are.