The kulcapi is a small boat lute from the Karo Batak people of North Sumatra. The kulcapi is made from one single piece of wood, in a slender diamond-shape. The body is hollowed out with on the back a diamond-shape sound hole.
The front is covered with a thin piece of wood, with the square bridge left as a block when the front was thinned. The neck has a number (about 7) of metal frets, inlaid in the front in a diatonic scale. Usually the top of the pegbox, and the end of the body (which bends back, not up like the hasapi) are decorated with stylised woodcarvings. The entire instrument is painted black.
-Playing the kulcapi is with a plectrum (often fixed with a rope), mainly to accompany singing.