Strategy is about advancing our position. To do this, we must move into new areas. This is what Sun Tzu calls a strategy of invasion. Armed March is one of the longest chapters in The Art of War. It takes a detailed look at how we adapt to specific situations that we encounter when we are moving into unfamiliar territory.

Though originally written about specific situations faced by armies in the field, this chapter works extremely well as a series of analogies. It works because of the deep, fundamental connection between the natural world and the competitive environment in modern society. When Sun Tzu discusses moving through mountains or marshes, on one level he is talking about physically moving through these types of territory. However, each of these situations has an analogue in our social environment. In society, we have mountains, rivers, marshes, and plateaus as well. We also have animals that gather at abandoned camps and startle at approaching armies.

We split the chapter into its second part, where the focus changes to interpreting the words and actions of others in the environment rather than the physical environment itsef.