These rules are due to the Domino 32 Company (PO Box 79168 Waverley MA 02479-0168) in their rule book. The game is Chinese origin, developed by the Domino 32 Company in the late 20th century.
The game uses a set of Chinese dominoes.
The object is to play each domino in your hand by matching one of its halves with the currently 'open' half in the playing area -- as in Western domino connecting games.
Like other Chinese games the winner of the last hand leads to the next. The winner of one hand has no other advantage besides the chance to lead in the next hand. The lead of the first hand is determined randomly.
The first player leads any tile. Then, in turn the next player (which in Asian games is the player to the right, giving us a counterclockwise order) may do one of two things:
Play continues until each player has played or discarded all eight of his tiles. The hand then ends and it is scored.
Each player scores the number of pips in all his discarded dominoes (which he should have kept face down in front of him). If one or more players place all 8 tiles and therefore have no discards, then other players scores are doubled. The winner of the hand (and lead player of the next) is the one with the fewest point in this hand.
If you make a train with the Chinese domino set, you will find that the ends are always 2 and 5 for the simple reason that these numbers appear an odd number of times in the Chinese Domino set. They cannot be paired like the other numbers.
Obviously, it is important what you discard, not just how many, since you score the number of discarded pips, not number of discarded dominoes. Because of this, most players usually lead a [6-6] or a [6-5] or whatever is the highest pip total tile in their hand.
The main strategy is to play defensively, keep a variety of 'halves' in your remaining hand so as to maximize the chance of playing a tile when it gets to your turn. Usually you cannot predict what the open half is by the time the others have played and the turn comes back to you.
In particular, there are only seven tiles with '2' as a half (two [2-2], and one each of [2-6], [2-5], [2-4], [2-3] and [2-1]). This short 'suit' is therefore a good suit to attack if you have plenty of it! That is, if you lead a [5-2] and declare the '2' open, then some other player would play another [2-n] tile, and that's two of the seven possible tiles already. It might be easy to eliminate all the '2's from everyone else and then leave a '2' as the open half, so that everyone else has to discard. Then, play your [2-2] to have another round with '2' as the open half, so everyone has to discard again!
In my short experience this is the only suit which can be attacked and 'monopolized' by one player alone. Other suits are not as short (although the '3's come close -- only [3-3] and [3-1] are Civilian suit tiles and therefore repeated, resulting in eight tiles overall). These 'sort-of short' suits can sometimes be 'duo-polized (instead of mono-polized)' -- two players who own most of this suit might catch on to what other is trying to do and team up against the leading player.