The Gusli is an old Russian instrument, a kind of a harp.

There were two modifications of gusli:

Slemovidnye gusli

(helmet-shaped gusli). Artist held this instrument on his knees, so that strings were horisontal, resonator body under them. He uses left hand to mute unnecessary strings and thus forming chords, while passing all the strings with his right hand. Was spread in southern and western regions of ancient Russia.

Krylovidnye gusli

(wing-shaped gusli). This instrument was much smaller, had more resemblence with
scandinavian harps, was held much more like modern guitars (although strings were still muted by the left hand through a special opening in the instrument's body). This modifications was more prelevant in northern parts of Russia, especially Novgorod and Pskov.