This script was created by Zanabazar, a famous Buddhist scholar at the end of the 17th century. It was also called a Mongolian horizontal square. The Zanabazar script was designed for writing in Sanskrit, Tibetan and Mongolian. It preceded the [BLOCK:soyombo Soyombo script], also created by Zanabazar. The Zanabazar script was not popular with contemporaries. However, it was rediscovered in 1801.

The square Mongolian script was based on [BLOCK:tibetan Tibetan]. It is an abugida, like the whole Brahmi family. The sound /a/ is added to all consonant letters, which can be neutralised by virama. Other vowel sounds are marked by signs above and below the consonant symbol, except for one independent — [U:11A00].

The Zanazabar script was to be written horizontally, from left to right.