Published in 1963 by "Circular Checkers, Inc." in Newfoundland, New Jersey, "The Sisti Challenge" is a Checkers variant. The publisher provided a round board consisting of 37 circles arranged in four concentric rings and split among two colours, and two sets of checkers (12 in each colour). As in traditional Checkers, the players' goal is to capture the opponents' checkers or to force the opponent into a position in which any legal move will allow the moving piece to be captured. The rules approximate traditional checkers, with only six circles in the outermost ring serving as "Kinging Circles." (These are the three rings for each colour that are farthest removed on the board from the opponent's home territory.) The construction of the playing area into a series of rings comprised of circles creates the necessity of several unique rules, specifically redefining "forward movement" (the motion of a checker toward its opponent's central kinging circle, the "Rules of the Nearest Circle" in movement and jumping that define which circles a checker may move to from its current position, and a "Single Combination Jump" which allows one checker jumping another within its ring to change directions and end in a separate ring.