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
Guitar chord are commonly played as barre chords, with the first finger depressing five–six strings. B major chord has the same shape as the A major chord but it is located two frets further up the fretboard. The F major chord is the same shape as E major but it is located one fret further up the fretboard. Minor chords (commonly notated as "C-", "Cm", "Cmi or Cmin") are the same as major chords except that they have a minor third instead of a major third. This is a difference of one semitone. To create F minor from the F major chord