Seven-string guitar string is augmented with a high octave string. Many of McGuinn's notable guitar solos utilize the G string of the twelve-string guitar to perform the main melody, and therefore the Martin seven-string guitar was designed to achieve this extended range playing without the need for doubling all six of the guitar's strings. In 2010, Inox Guitars has created a mix of the Brazilian Viola caipira and the Russian semistrunka (семиструнка). This instrument has 2 bass strings (as the 6th and 7th strings of the semistrunka) and five treble courses (as the Viola caipira) and it is used in open tuning
Zero fret Zero fret A zero fret is a fret placed at the headstock end of the neck of a banjo, guitar, mandolin, or bass guitar. It serves one of the functions of a nut: holding the strings the correct distance above the other frets on the instrument's fretboard. A separate nut is still required to establish the correct string spacing when a zero fret is used. The zero fret is positioned at the location normally occupied by the nut. On a guitar having a zero fret, the nut is located behind the zero fret and serves solely to keep the strings