About Portuguese Guitar:

 

With Origin on the european cithara, the Portuguese Guitar was changing through the years, existing today in two distinct formats: Lisbon and Coimbra

The Coimbra Guitar is characterized by the "tear" that ornaments the top of the guitar and its sonority lower than the Lisbon guitar.

The Lisbon Guitar has the "volute" on the top of the guitar and the tunes with the notes B-A-E-B-A-D.

Coimbra Guitar tunes with a tone below, it tunes with the notes A-G-D-A-G-C.

Although, all guitarists consider that the notes to tune the guitar are B-A-E-B-A-D, as if with these notes the guitar it on it's natural tune.