ZÈRTZ
ZÈRTZ is the third game in the "GIPF" Project of seven abstract strategy games. The game features a shrinking board and an object that promotes sacrifice combinations. It is impartial: since neither player owns on-board pieces, maintaining the initiative is of fundamental importance. Rules. Equipment. The playing pieces are six white, eight gray, and ten black marbles, and (for the standard game) 37 rings, each of which can hold a marble. (Advanced players use up to 61 rings.) Setup. Players place the rings on a flat surface and arrange them as a packed hexagon, as regularly as possible . This composes the "board". With 37 rings, this forms a perfect hexagon with four rings on a side. The marbles go into a shared pool. Object. The object is to capture three white, or five gray, or six black marbles, or three marbles of each color. (A quicker variant can be played in which the object is to capture three white marbles, or four grays, or five blacks, or two of each color. See below.) Jumping. If any two marbles are adjacent on the board, and there is room for one to "jump" the other, landing on a ring immediately  opposite the other, a player must jump instead of dropping. The jumping player captures any jumped marbles. The player must continue to jump with the same ball as long as additional jumps by the same ball are possible. If at any stage of jumping more than one jump is possible, the player may choose whatever direction he pleases; he must, however, continue jumping with the same ball for as long as at least one other ball is jumpable by that ball. (This is similar to the compulsory jumping rule in Checkers.) No rings are removed on a jumping turn. Dropping . If no jumps are available, the player whose turn it is must drop a marble of any color onto an empty ring of the board, and take a removable ring from the board. A ring is removable if it can be detached by sliding it away on the table surface without displacing other rings. If removing a ring produces a cluster of one or more rings, called an "island", with a marble on each ring in the cluster, all of these rings are also removed, and the player whose move created the island captures all the marbles on it. If  no ring is removable, the player's turn ends when he drops a marble. If no marbles are available in the shared pool, the player must drop one of his captured marbles instead. Strategy. The basic strategy in "ZÈRTZ" is sacrifice. Because a player is forced to capture when possible, a common strategy is for one player to play so that the other must capture a piece of low importance. This moves other pieces into a position where the first player can then capture one or more pieces of higher importance. In addition, sacrifices are used to arrange pieces and  gain time in preparation for capture by isolation. Frequently a game will end with one player forcing the other to repeatedly jump, gaining time to win with a capture by isolation. Variants. Blitz. A short version of the game can be played using only 5 white marbles, 7 gray, and 9 black marbles. In this case, the goal is to capture only three whites, four grays, five blacks, or two of each color. This variant is described in the original edition as the "basic rules". Section::::"ZÈRTZ"+11. This is the game of "ZÈRTZ" played with 11 extra rings, forming an irregular  hexagon with sides alternating between 4 and 5 rings. This is the current standard for serious tournament play. Section::::"ZÈRTZ"+24. This is "ZÈRTZ" played with 24 extra rings, forming a regular hexagon with 5 rings along each side. It has been suggested that this will eventually become the tournament standard ().