Min-maxing is the practice of playing a role-playing game, wargame or video game with the intent of creating the "best" character by means of minimizing undesired or unimportant traits and maximizing desired ones. This is usually accomplished by improving one specific trait or ability by sacrificing ability in all other fields. This is easier to accomplish in games where attributes are generated from a certain number of points rather than in ones where they are randomly generated. Min-maxing is particularly common in games where the cost of traits does not reflect their expected usefulness; for instance, in a combat-heavy game a player may focus on physical traits, giving a character abnormally low mental and social skills so that the remaining points can all be channeled to physical statistics that are more likely to come into play.
Min-maxing is usually associated with powergaming, though the two are not necessarily the same; min-maxers often min-max during character creation but play the game the same as any other player, and powergamers often create characters within the normal scope but then proceed to build them up by earning their power-ups during gameplay. A certain amount of min-maxing is expected and even desirable, as it indicates interest in the game, but beyond a certain threshold it becomes destructive to the game.
As an example from the MMORPG City of Heroes, the Scrapper (a powerful offensive melee class) can sacrifice enhancing the accuracy of melee attacks (the Min) by enhancing the attacks' damage and attack rate (the Max). They then restore much of the missing accuracy using other techniques such as the high level alternative power Focused Accuracy, though this particular mini-max strategy has been greatly impacted by the introduction of both Enhancement Diversification and the introduction of IOs (Invention Origin crafted multi-purpose enhancements).
A similar phenomenon exists in strategy wargames, where the Min-Maxer, during army selection (the analogue of character creation) takes the absolute minimum of the basic, compulsory forces (the Min) in order to gain the highest possible proportion of specialized, powerful troops (the Max). This can work in an overall army or in a squad.
For example, in the Warhammer 40k system (where an army is based around 1-2 HQ choices, 2-6 Troop choices, and 0-3 each of Fast Attack, Heavy Support and Elite choices), a min-maxed army may comprise of 2 of the smallest, cheapest possible "Troop" choices, then 2 min-maxed Special Characters or HQ troops, 3 Elite, 3 Fast Attack and 3 Heavy Support choices. In a squad, an example includes taking a minimum sized scout squad of 5 troops, then upgrading one with a Heavy Bolter or Missile Launcher, in effect that squad being use solely for the purpose of gaining that special weapon. A common name for min-maxing an entire army is "Cheese", "Cheese Factory" or "Cheesing".