A large inspiration for the Wardley Mapping method comes from Sun Tzu's The Art of War, and from John Boyd's OODA Loop. The five factors of competition described by Sun Tzu were Purpose - Landscape - Climate - Doctrine - Leadership. 
Simon has related these to Boyd’s phases of a battle: Observe, Orient, Decide, Act.
It doesn't matter whether you're competing against a foe in a battlefield, or in a game of chess or in business ... strategy always starts with where. "Where can I move?" is the first question you must ask. To do this then situational awareness (i.e. understanding your environment) is critical. If you cannot visualise (even through mental models) the landscape then you cannot determine "where". Mapping is fundamental to strategy and to organisational learning (e.g. economic lessons and repeatable gameplay in business or battle plans in military history) because situational awareness is.
Landscape is the environment that you compete in. It describes the position of troops, the features of the landscape including any obstacles in your way.
In Wardley Mapping, we document the landscape using a particular kind of map, which for lack of a better term is often called a Wardley Map. It has a vertical axis labeled “Visibility”, and a horizontal axis labeled “Evolution”. Components are drawn on the map as simple symbols, typically labeled circles, with lines connecting related components. A map is drawn by placing a customer / user at the top, and then drawing a line to a circle below labeled with the user’s need. From the user’s need lines are drawn to the next lower layer of circles, with each circle labeled as, and representing some necessary component in fulfilling that higher-level need. This process repeats until every ingredient or sub component required to deliver a customer need is drawn.
The vertical “visibility” axis has no scale or sections - it is purely a relative positioning, with components closer to the top of the map being more visible to an end user, and components lower in the map being less visible. Visibility implies how much an end user of the product you are mapping notices or cares about a particular component.
The horizontal “evolution” axis is divided into 4 major sections, typically labeled from left to right as “genesis”, “custom”, “product / rental”, and “commodity / utility”. Several other labeling are possible based on what kind of component is being mapped. Regardless of the name, each section has unique characteristics, which are roughly:
- Very early-stage ideas with no end-users and little certainty about their usage or value. These are experiments that may or may not turn into useful products.
- Components that are made individually for each usage, and have limited public adoption.
- Components that are produced by several competitors, have some established market of customers, and increasing levels of certainty about specifications and usage.
- Components that have matured to the point that there is little visible improvement or difference in specification, and a wide range of customers understands how and when to use it.
More specific guidance can be found on the Mapping cheat sheet.