There is no general governing body for this event.
Doubles can be played as a suit of their own, and can only be played high in their suit.
Dealing: A dealer is selected by shuffling the dominoes face down on the table. Each player draws a domino; the player drawing the highest number of dots is the first dealer. The dealer then re-shuffles all dominoes face down. Players draw 7 dominoes to begin the hand. Following the hand, the deal moves clockwise around the table.
Bidding: The player sitting to the left of the dealer is the first bidder. The bid moves clockwise around the table until every player has the opportunity to bid by raising a previous bid or passing. Each player has only one chance to bid before play of the hand begins.The bidding begins at 30 and moves upward to 42 [One Mark]. However, if a player feels he can take all the tricks -- or wants to play Nel-O and try to lose all the tricks (see below) -- he can declare a bid of 42 [One Mark] or 84 [Two Marks]. "Mark" bidding may not start at 126 [Three Marks] or higher. After a 42 or 84 bid, subsequent bids must be made in one Mark increments. All Mark level bids must be stacked. To speed up play, no "Pass Out" hands will be allowed. If the first 3 players pass, the 4th player must bid a minimum of 30. The highest bidder announces trumps and starts the game by playing the first domino. No trumps ("follow me") is allowed. Players must follow the suit led by the first player of each trick. If trumps are not led, the highest suit on the domino led establishes the suit a player must follow. If it is not possible to follow suit, then a player may throw a trump, a count domino, or an "off." Trumps cannot be played if it is possible to follow suit with other dominoes. The highest trump or highest domino takes the trick. When doubles are trumps the same trump rules apply: the lead of a double requires play of a double, when possible
Scoring: There are 7 tricks that make a total of 42 points. To determine if a bid is made or not, add the number of points in the bidder's tricks. If they do not total the amount bid or more, he is "set". Tricks with count dominoes in them still count 1 point for the trick
Nel-O: Playing Nel-O will be allowed. A player bidding 42 "Nel-O" turns his partner's hand face down and eliminates him from play during that hand. In a Nel-O hand, before play starts, the bidder must state whether doubles will be part of individual suits or a suit of their own. If doubles are high in their suit, a double must be played if it is the only domino in the player's hand that is the same suit as the domino led. If doubles are a suit of their own and when a double is led, you do not have to follow suit if you do not have a double.
Suits: There are 7 dominoes in each suit, six with the number of dots on one end being the same and one with the number of dots on both ends the same. The latter is called a double. Doubles can also be classed as a suit in the same order of importance: 6-6, 5-5, 4-4, 3-3, 2-2, 1-1, 0-0. There are a total of 8 different suits: Blanks, 1's, 2's, 3's, 4's, 5's, 6's and doubles.
Trumps: The highest bidder's suit becomes the main trumps for the duration of one hand. Trumps are higher than any domino and will take tricks including doubles of other suits.
Offs: Any domino in a bidder's suit becomes the main trump for the duration of one hand. Trumps are higher than any domino and will take tricks including doubles of other suits.
Walker: Any domino which not been played and is the highest in its suit after the double and other higher ones have been played is said to be a "walker".
Count Dominoes: There are 5 count dominoes in double six sets of dominoes, 5-5 and 6-4 which count 10 points, and 0-5, 3-2, and 1-4 which count 5 points.
Trick: A trick consists of 4 dominoes, each player playing 1 domino in clockwise rotation around the table. There are 7 tricks to each hand.
Count: Each trick counts 1 point plus the values of "count" dominoes in each trick.