That is, for letters of the first and second decade of the braille script (a, c, e, l, n, s), a diacritic is written as dot 6, and any dot 3 is removed (or, equivalently, is moved to position 6)—that is, the base letter is moved to the fourth decade. For letters of the third decade (u, y, z), which already have a dot 6, the derivation is a mirror image. Ó is derived from u, which is how it is pronounced (also, the mirror image of o is already taken). Several of these conventions are used in Lithuanian Braille.
History
Some form of a Braille alphabet had been adapted to the Polish language by 1957.[2]
^It is not clear which brackets these are. In Polish, their name is nawias wydzielający, a phrase that refers specifically to these braille characters.