Found throughout much of the world from New Guinea to Spain, this is not a harp at all and has no historic association with Jewish traditions.

Its name might be a mistranslation of a French word, 'jouer', which means 'to play'. In 15th and 16th century Britain, it was called a 'Jew's Trump'. In 19th century Italy, 'scacciapensieri' - loosely translated, this means 'to chase your thoughts or troubles away'. In contemporary Spain it is called the 'trompa inglesa', which suggests that it was imported (though not necessarily from Britain).

Technically categorized as 'plucked idiophones', these instruments have a thin frame with either a rectangular, onion/lyre or elongated shape. One end of the frame is closed, the other end left open. Attached to the closed end is a single key or tongue, usually made from the same material as the frame.

There are two main kinds of instrument. The oldest are made of bamboo. In these, the free end of the tongue remains confined within the frame and the tongue itself is moved in various ways but not plucked. Such instruments are found in Melanesia, Indonesia, South-east Asia and China, as well as Tibet, Nepal and India, which marks the western boundary of their area of distribution.

In the other type, made of forged metal (usually iron, sometimes silver), the free end of the tongue overlaps the frame and is plucked with the finger. This kind, still used sporadically in Europe, is Asian in origin and is mainly played by mountain populations in Vietnam, Cambodia, Nepal and Afghanistan.

Playing the instrument involves holding the closed end in the mouth and setting the tongue in motion, using the mouth cavity as a natural resonating chamber. Different pitches and sounds can be made by changing the size and shape of the mouth, which accentuates and amplifies certain harmonics of the fundamental note given by the instrument.

There is a rich oral tradition associated with the jaw's harp. In New Guinea, it is used as a traditional ceremonial instrument, often played exclusively by men at religious events. Among certain Asian communities, it has been used to serenade loved ones; when left as a gift it might be considered a proposal of marriage. In Austria during the early 19th century, silver jaws harps or 'maultrommel' were reportedly banned by authorities who considered them instruments of seduction.