Russian guitar usually differs from the wood in the rest of the neck. The neck joint or heel is the point at which the neck is attached to the body of the guitar. The fingerboard is made of hardwood (ebony or rosewood are common), fitted with metal frets of brass or steel. Fret spacing almost always follows the western twelve tone equal temperament (12-tet) system. The surface of the fingerboard may be flat or curved slightly ("radiused"), although the curve on the Russian guitar is usually somewhat less than that of an equivalent western 6-string guitar. Inlayed position markers are common, and
Eight-string guitar and six-string variants. The standard tuning (from low to high) is F#, B, E, A, D, G, B, E. Many prefer to tune the F# to a low E (E1), the same note as the lowest string on a four-string electric bass in standard tuning, and providing the guitar with a fuller sound by having three different E strings. Like the seven-string, the first mass-produced eight-string guitar was made by Ibanez guitars in Japan; the RG2228. The main design issue faced with an eight-string guitar is tuning stability with the lower strings. This is due to the neck being constructed