The success of the original Risk game led to specialized versions. In 1986, for example, a variation called Castle Risk was introduced in Europe. It scaled down the playing field, and required players to invade or occupy only European countries. Another variation of Risk that emerged in the 1980s was the "secret mission" version, which allowed players to receive a secret mission that, if accomplished, would win the game. Yet another version, Risk: Napoleon Edition, was introduced in 1999. It was similar to Castle Risk, but with modifications that were based upon Napoleon I's military campaigns. The version also added additional pieces, such as generals, fortresses and naval units. But perhaps the most unusual new edition was Risk: 2210 A.D., released in 2001, which included a time limit and used a point system, rather than total territory domination, to determine the victor [source: Hinebaugh].
Risk also is sometimes played with "house" rule variations created by gatherings of veteran players, which can make the game more difficult or interesting. Some like to play timed matches, or limit the number of turns players get, which deprives them of the leeway of waiting for opponents to self-destruct. Another variation of Risk, one possibly dreamed up by a geography teacher, requires players to demonstrate knowledge before they place armies in a territory or attack it. In order to proceed, a player has to identify a specific state, province or country that's within the territory. Another twist is to play Risk on an actual map, instead of the standard board, and to create your own territories that are in play. For example, Risk can be played on a map of the United States, with players holding various states and attacking others. Enthusiasts also have converted Risk into a historical knowledge game, with players required to answer questions about historical conflicts, such as World War I, before they can place armies on territory or launch an attack [source: Hinebaugh].