Chinese dominoes can be grouped in different ways. So far, we have seen groupings of two – in pairs, which is explained in more detail in the article Tiles and pairs hierarchy. In some games, it was possible to group three dominoes if their sum is divisible by 10 without a remainder (such as in Tau Ngau, or Tsung Shap).
There is another way to group three dominoes, which we will call Triplets, or Classical Triplets. In the original, they can be found under the name 宣和牌谱. This method is found in some games, as well as in fortune-telling. Probably, this method of grouping tiles originated from fortune-telling.
In order to better understand how triplets are formed, it is necessary to consider each tile as two halves. So, one triplet is six halves of a domino, for simplicity we will call them “values”. And what plays a role is not which dominoes make up the triplet, but which halves or values. That is, for example, the triplet [1:2][2:3][1:3] is considered the same as [1:1][2:2][3:3], because even though it consists of different tiles , but the set of values there is the same.
There are nine types of triplets, which can be divided into three groups.
The first group includes triplets in which exactly three values are the same, no more and no less.
- Five points (五點) – three identical values, the sum of the remaining values gives exactly five, for example [6:3][6:6][1:1]
- Full fourteen or Speed (正快) – three identical values, the sum of the rest is fourteen or more, for example [6:5][6:5][5:3]
- Split (分相) – three identical values and three more identical values, for example [3:3][3:1][1:1]
The second group includes triplets in which there are more than three identical values:
- Coincidence (合巧) – four identical values, and the sum of the remaining two values coincides with this same value. That is, for example [5:5][5:3][5:2] is four fives, and the sum of 3+2 is also five. Or [2:2][2:2][1:1]
- Five sons (五子) – five identical values, the sixth value does not play any role. For example [6:6][6:6][6:3]
The third group includes the so-called “dragons”, where there are less than three identical values.
- Full Dragon (全龍) – all values are different, for example [6:1][5:4][3:2]
- Big Dragon (大龍) – two sixes, two fives and two fours, for example [6:5][6:5][4:4]
- Little Dragon (小龍) – two ones, two twos and two threes, for example [1:1][2:2][3:3]
- Two-Three-Kao (二三靠 or 双飞燕) – two twos, two threes and two sixes. For example [6:3][6:2][3:2]
It is difficult to write about the history of these triplets, since all the information about them is in Chinese, besides, it is difficult for me to separate fiction from facts. But it seems that these combinations played an important cultural role in the history of Chinese dominoes. Poetic names were invented for various combinations and poems were written for them. For example, the combination [5:5][5:1][5:5] looks like a sunrise between plum blossoms, and that’s how it was called.
Previous combinations are classic. Sometimes there are additional ones that either supplement or replace the classic ones. They will be mentioned in the relevant sections.
Also, these combinations took part in fortune-telling. The simplest form of fortune-telling was to put dominoes in a row and look for triplets that were there. There was a special book to explain triplets.
Chinese Dominoes GuPai 