Scholars of medieval history know that the game of Chess existed in multiple forms during earlier centuries, such as four-hand chess, courier chess, and circular chess (this last is still played regularly). It is less well known that the game Jeopardy! has another form, only ever played by lawyers. This is known as Double Jeopardy, and the single difference is that if a player (known as a prosecutor) tries to win, and loses, he is allowed to try again. Given the problems inherent in this situation (where a game might never be properly finished, as the loser will always try again), the game has fallen into disrepute. In fact, a “Rule Against Double Jeopardy” has been introduced to prevent it being played in official venues.