 Early role-playing games were derived from skirmish wargames, and many are still played as such.Many early designs for man-to-man games had cumbersome pre-plotting of moves, others used a system of multiple maps and umpires to try and create "fog of war" or uncertainty for players.Modeling conflict at this scale provides unique challenges to the game designer, who must find a way to quantify variables such as human behaviour at an individual level; games at higher (grand strategic, strategic, operational or tactical) levels can arguably have their variables more easily quantified.