“Earth comprises distances, great and small; danger and security; open ground and narrow passes; the chances of life and death.”
And so, “Earth” represents the terrain.
“Earth” represents the details of the environment that may change greatly, even over a short distance. Ignorance of these details courts disaster.
When real estate agents speak of the three factors affecting the value of a piece of land as “location, location, location,” they are speaking of “the Earth.” When Chinese house hunters recoil in horror at a property because a street is aimed directly at the front of the house perpendicular to that which runs in front of the house, thus bringing evil directly to the front door according to feng shui, this is a consideration of “the Earth.” However, this does not mean physical terrain alone.
There is a different kind of terrain: the human terrain. Humans vary greatly from place to place, and even from individual to individual; it is in-depth knowledge of the differentiations between people, their thinking processes, their actions, and their deeper human nature, that provides the strategist with a great advantage. Everyone can see what is on the surface; the strategist looks deeper to see what is intangible, invisible to the naked eye.
Thus does the strategist find advantage where others do not.