Before revision: The Qinling–Huaihe Line was defined by Chinese geographer Zhang Xiangwen in 1908, defining north China as anything above a line running along the Qinling Mountains in the west and the Huai River the east.
After revision: In 1908, Chinese geographer Zhang Xiangwen defined northern China as anything above a line running along the Qinling in the west and the Huai River the east.