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
Scale length (string instruments) All other things being equal, increasing the scale length of an instrument requires an increase in string tension for a given pitch. A musical string may be divided by the twelfth root of two formula_1, approximately 1.059463094 and the result taken as the string-length position at which the next semitone pitch (fret position) should be placed from the previous fret (or, in case this is the first calculation, the nut or zero fret) of the instrument. This quotient is then divided again by itself to locate the next semitone higher, and so on. Alternatively, the string may be divided by