Comments by "disgruntledtoons" (@disgruntledtoons) on "The Game of Risk - Numberphile" video.

To win the game you must attack on as many turns as possible. You get a card at the end of each turn during which you take a territory, and turning in sets of cards earns the player doing so progressively higher numbers of armies each time this is done. After a while the armies gained for doing this are ridiculously high, and in a long-running game this provides the majority of the armies raised during the game.
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