# Eight-dot braille cell

We can form an eight-dot braille cell by adding a fourth row of dot positions below the usual six-dot braille cell. This eight-dot braille cell has eight dot positions arranged in two columns and four rows. We traditionally number these dot positions from one to eight in such a way as to retain the usual numbering for the dot positions for the upper six dot positions:

- First or top row, left-hand column
- Second row, left-hand column
- Third row, left-hand column
- First or top row, right-hand column
- Second row, right-hand column
- Third row, right-hand column
- Fourth or bottom row, left-hand column
- Fourth or bottom row, right-hand column

Row | Left-hand column | Right-hand column |
---|---|---|

First or top row | 1 | 4 |

Second row | 2 | 5 |

Third row | 3 | 6 |

Fourth or bottom row | 7 | 8 |

A dot can be either present or absent in each dot position. A cell with eight dot positions gives 256 different characters, because 2 raised to the power 8 is 256.

We can represent a braille character in words by listing the numbers of the dot positions where dots are present. For example, we can refer to a braille character that has dots in dot positions 1 and 5 as "dots 1 5" or "dots 1-5" or, slightly more concisely, as "dots 15", all of which we read as "dots one five".