By opening and closing the end of the tube with one finger tip (best is the middle finger, while holding the flute between thumb and ring finger) and each time applying more pressure, a simple harmonic scale can be played.
The overtone flute can be found in the Balkan region, Slovakia, Poland, where it is called koncovca, in the Scandinavian region the flute is also played and called selyefloyte. Very similar to these flutes are the sepic flutes, the long flutes of indigenous people of South-America, who use them in rituals. The overtone flutes on offer here are of the koncovca type, with a precisely made fipple, so no special embouchure (blowing technique) is needed. These flutes are made of single branches, mostely of elder. The center of the wood is drilled with special drills, taking out the core, and leaving the branche structure intact.
Overtone branche flute in 'G'
Overtone branche flute (rosewood) in 'A#'
Overtone branche flute in 'B'
Overtone branche flute in 'C'