Let me get this straight. Zhang Xun and his forces of 60,000 people were in a battle or conflict for so long that they ran out of food, ate the horses, and the procedure to resort to cannibalism, first starting with the woman, then the old men, then the young boys, and then from there picking the weakest of the group that was left for who would get eaten next until the force was down to 400 survivors? And they considered it acceptable losses?
I imagine it was considered a strategic Tang victory even though it resulted in a loss of the city, because without the time bought by the seige, the Tang would not have been able to put down the rebellion.
The Taiping Rebellion. Basically a Chinese guy claims to be the brother of Jesus and leads a pro-Christian rebellion against the Qing government that results in more deaths than the first world war