sentences:  Games such as "Rise and Decline of the Third Reich", "Empires in Arms", and "Empires of the Middle Ages" are true wargames, in the sense that military units are specifically represented, and engage in direct combat based on specific military attributes.The "Hearts of Iron", "Europa Universalis", "Crusader Kings", "Supreme Ruler Ultimate" and "Total War" series are examples of computer-based grand strategy games.Games use various techniques and features to simulate aspects of national military strategy.