Dongguan was a mysterious little city somewhere in the south in later generations, famed throughout the world because of a crackdown.
But during the Eastern Han, Dongguan was not in the south. It lay in Xuzhou and was one of Langya Commandery's key strongholds.
The reason Lu Bu had Zang Ba station troops in Dongguan rather than Ju County to the east was that Dongguan lay along the Yi River waterway.
Following the Yi River south, passing through Dong'an and Yangdu, one could strike directly at Kaiyang, the commandery seat of Langya.
Lu Bu had Zang Ba block this route to prevent Yuan Tan from moving south and launching a surprise waterborne attack on Donghai Commandery.
But even if he were beaten to death, he would never have imagined that Zang Ba would suddenly rebel, turning Dongguan's terrain into an aid for his advance instead.
After listening to Xu Shu's persuasion, Zang Ba led more than twenty thousand troops under Sun Guan, Wu Dun, Yin Li, and the others southward along the river.
Within a few days, Zang Ba successively broke through the three counties of Dong'an, Yangdu, and Kaiyang, gaining control of the Yi River waterway.
He then made Sun Guan the vanguard, ordering five hundred cavalry to move ahead. Traveling more than eighty li a day, they launched a surprise assault on Xiangben and boldly charged into Donghai Commandery.
At the same time, after Yan Jun and the others in the west received Xu Shu's message, they led more than ten thousand troops in a surprise attack on Xiao County.
In just one day, they seized Xiao County, the gateway to Xuzhou, then charged toward Pengcheng.
These two sudden armies nearly shook all of Xiapi, giving Chen Gong, who had remained behind in Xiapi, quite a fright!
Xu