Improving Decision-Making Through Games - From the Green Notebook
War games are a great way to learn about history and warfare.
The Prussians used war games in the 19th c. to prepare for conflicts. So did the WATU (the UK Western Approaches Tactical Unit), and the US Navy. These organizations had the benefit of time, space, and resources, but the same benefits are often unavailable to the officer who wants to learn in his free time.