Why Double-Six Has 28 Fichas

Start with the seven possible values on one half: 0 through 6. Blank can pair with all seven values, including blank. One then adds six new pairs, because blank-one already exists. Continue with five new pairs for two, then four, three, two, and one.

The sum is 7 + 6 + 5 + 4 + 3 + 2 + 1 = 28. The general pairing formula is x(x + 1) / 2, where x is the number of possible end values: 7 × 8 / 2 = 28. The University of Tulsa puts it another way: the 21 combinations of two dice plus seven tiles with a blank. The same count gives 55 tiles for a double-nine set and 91 for a double-twelve.

Each value appears on seven Fichas. The six suit, for example, runs from blank-six through six-six. The seven doubles are blank-blank, one-one, and so on through six-six.

The 28 tiles hold 168 pips in total. Each value appears on seven tiles, and the double shows it twice, so each number appears eight times: 8 × (0 + 1 + 2 + 3 + 4 + 5 + 6) = 8 × 21 = 168.

Dominican tables deal seven Fichas to each of the four players, as the linguist Roberto Guzmán writes in Acento. Four hands of seven account for all 28, so nothing remains face down to draw.

That complete deal is strategically important: every Ficha is either in a player's hand or eventually visible on the table. Passes and played suits therefore give information that a draw game does not provide in the same way.