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
Ten-string guitar Ten-string guitar There are many varieties of ten-string guitar, including: Harp guitars are guitars to which extra strings have been added which are never fretted but may be plucked or strummed. These strings are therefore played in a manner similar to those of the harp, while those of the principal neck are played as a guitar, hence the name. Often a second neck, parallel to the fretboard, carries these extra strings. There have been many designs of harp guitar, but in the nineteenth century ten-string versions were particularly popular. Information on nineteenth-century harp guitars comes from three main primary sources: