Yarkand River
In 1897 a British military officer, Sir John Ardagh, proposed a boundary line along the crest of the Kun Lun Mountains north of the Yarkand River. At the time Britain was concerned at the danger of Russian expansion as China weakened, and Ardagh argued that his line was more defensible. The Ardagh line was effectively a modification of the Johnson line, and became known as the "Johnson-Ardagh Line".