The single string is plucked openly with one finger or a plectrum. The pitch can be lowered considerably by pressing both halves of the forked bamboo neck together, thus reducing the tension of the string. The fixed 'tonic' is in this case the note of the open string when the neck is not pressed. All other notes are lower than this. Apart from the open string note it is very difficult to produce any precise pitch. However, it is very easy to produce typical floating wobbly sounds that's what this instrument is made for!
Sorry no pictures yet!