The Art of War by active 6th century B.C. Sunzi

2. Camp in high places,

[Not on high hills, but on knolls or hillocks elevated above the surrounding country.] facing the sun. [Tu Mu takes this to mean "facing south," and Ch’en Hao "facing east." Cf. infra, §§ 11, 13. Do not climb heights in order to fight. So much for mountain warfare.