The Game
Risk is a turn-based game for 2 to 6 players. It is played on a board depicting a stylised political map of the world, divided into 42 territories, which are grouped into 6 continents. To start, each player rolls one die. The player who rolls the highest number plays first and the sequence goes clockwise. Each player in turn places one unit of "army" on the territory to claim land until all armies are placed.
The game is played by allocating armies to the territories that you control, and then attacking neighbouring territories in order to conquer them. The outcome of battles is decided by rolling dice. A player is eliminated if they lose all of their territories.
Each player receives reinforcement armies at the beginning of their turn - the number of reinforcements depends on the number of territories controlled, with bonuses for controlling all territories in a continent (see table below). A large part of the strategic skill of the game lies in deciding how to deploy these reinforcements.
It is possible to win by controlling all 42 territories on the board (and so eliminating all other players). However, this results in a very long game, with a drawn out and predictable end game. Therefore, some versions of the rules specify a lower winning target (typically 24 territories), or allocate a random, secret, "mission" to each player at the beginning of the game. Possible missions include gaining control of all territories in two or three specified continents, or eliminating another specified player; the first player to achieve their mission wins the game. With missions, a typical game of Risk lasts two to four hours.
Since playing Risk with fewer than three players isn't always as engaging as games with more players, some versions of the rules recommend having some territories occupied by "neutral" armies to give the same strategic value and fun factor as an actual three-way game.
Risk Strategy
The strategy of Risk is to have the most number of armies in the place where they will do the most good. One of the easiest ways to gain armies is to hold continents. If you hold an entire continent for an entire turn, you receive an number of extra armies, which is dependent upon the continent.