This is a member of the Fives family of games. The difference is the way that the first double is used as a spinner. This was reported to be John Wannamaker's favorite game by Dominic C. Armanino in one of his books. For the younger readers, John Wannamaker was famous for his chain of department stores.
The game uses a double six domino set. The game can be played by two to four players. The four player game is usually a partnership game. A cribbage board is useful for scoring, since scores are totaled as they are made and not at the end of the hand.
The size of the hand varies with the number of players:
The first player in the first hand is determined by lot. In the following hands, the player who dominoed in the previous hand plays first. If the last hand was blocked, then the lead is again determined by lot. The lead can be any tile in the player's hand. The next players must match the ends of the tiles on the table.
The first double, and only the first double, played is used as the Sniff. It is played in line, but then the players can add one and only one tile to either side of the Sniff, making it into a spinner. The open ends of these two tiles are computed into the total for the rest of the game. The Sniff looked and acts somewhat like a stubby spinner, but you cannot grow its two arms.
Grady and Goldberg (DOMINOES; Gamescape Publications; ISBN 1-887594-01-9; 1995) and Dominic C. Armanino give a version of the game as played in the United States. The Sniff is turned crosswise and acts like a regular spinner in play. The difference is that the ends of the Sniff continue to count toward the total while they are exposed.
For example, assume the [4-4] is played first; the total is eight. The [6-4] is played next; the total is (4 + 4 + 6) = 14. the [1-4] is played next; the total is (4 + 4 + 6 + 1) 15. Once tiles are played on all the arms of the Sniff, the game is just like All Fives. In this version, the hands are smaller.
The second and following doubles are turned crosswise, and count as the total of their pips for scoring purposes while they are on the end of an arm, but are neither played as spinners nor counted as a Sniff.
If a player cannot play a tile, he must draw tiles from the boneyard until he has a tile which will play or the boneyard is empty. When he draws a tile which will play, it goes on the table immediately and his turn ends. If he empties the boneyard and still cannot play, he passes and the next player takes his turn.
The hand continues until one player dominoes or until all players are blocked.
After a player has set a tile, the two, three or four ends of the layout are totaled. If this total is a multiple of five (5, 10, 15, 20, 25 or 30 points), the player immediately scores that number of points. The turned doubles on an arm of the layout score the total of its pips; that is [5-5] is worth ten points, [6-6] is worth twelve point and so forth.
When the hand is finished, either by being dominoed or by being blocked, the pips on the tiles remaining in each hand are totaled and the total is rounded up or down to the nearest multiple of five. For example, a hand with [1-2] would round to five points, while [1-1] would round down to zero points. These points are then subtracted from that player's score.
The game is played for 200 with three or four players and for 250 points with two players.
There are several variations of this game, all of which deal with how to handle or score the Sniff.
1) Fredrick Berndt (THE DOMINO BOOK; Bantam Books; ISBN 0-84-07601-4; 1975) gives a version of Muggins under this name where the Sniff can be played either in line or crosswise. If it is played in line, then only one end is counted in the total. If it is played crosswise, then both ends are counted in the total in the usual manner. For example, assume that the table has [6-1] [1-4] on it as the tableau. The [4-4] can be played crosswise and the total will be 14 points, or it can be played in line and the total will be 10 points. The Sniff is still a spinner. If the Sniff is played crosswise, the next tile added to it must be on the side before the ends can be played upon; if the Sniff is played in line, the next tile added to it must be on the end before the sides can be played upon.
2) A British source gives these rules for handling the Sniff. The first double, and only the first double, played is used as the Sniff. If it is played in line, players can add one and only one tile to either side of the Sniff. The open ends of these two tiles are computed into the total for the rest of the game. The Sniff looks and acts somewhat like a stubby spinner, but you cannot grow its two arms. If the Sniff is played crosswise, then the usual rules for All Fives apply.