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
Twelve-string guitar downward strum is the higher-octave string; however, Rickenbacker usually reverses this arrangement on its electric 12-string guitars. The tuning of the second string in the third course (G) varies: some players use a unison string, while others prefer the distinctive high-pitched, bell-like quality an octave string makes in this position. Another common variant is to tune the octave string in the sixth (lowest) course "two" octaves above the lower string, rather than one. Some players, either in search of distinctive tone or for ease of playing, remove some doubled strings. For example, removing the higher octave from the three bass