That bitterly cold winter the Grand Canal had frozen, and Nelson roared down the old Imperial Highway beside it until he reached open water eighty-three miles south of Tsingkiangpu, at Kaoyu.
Kaoyu, with its back against the Kaopao Lake, had "the lake serving as a barrier" and was also an important stronghold covering T'aichou, Chang's strategic town for river defense; militarily it must not be abandoned lightly. But, more importantly, Chang, formerly a salt dealer, always regarded Kaoyu as his mecca.
