The Ja-khay is a large plucked string instrument which is played by placing horizontally on the floor in front of the musician.
         The body of the Ja-khay is made of wood from the jack-fruit tree (Kha-noon in Thai) hollowed out to serve as a resonance box. The sound box is covered with a thin sheet of wood, perforated for a sound channel. There are three strings along the top of the body—two silk strings and a brass wire. Each string is attached to a tuning peg at the ‘tail’ end of the instrument. (At present the nylon string is widely used in place of silk.) The strings are lined up over a small brass box called “Toh”, on which a thin slat of bamboo is fixed to produce the unique characteristic twanging sound of Ja-khay known as “Gin Nhae”. On the body of the instrument there are 11 frets (Nom) made of Moke wood in different heights. The three strings are lined up over these frets to the “Soom” and duck under a small groove called the silk groove (Rang Mai) before being attached to the tuning pegs.
         To play the Ja-khay, a tapering cylindrical plectrum made of hard wood, ivory, horn or animal bone is used. The plectrum is tied tightly to the index finger of the player’s right hand to make a loud and distinctly clear sound.
         The Ja-khay has been in popular usage since the Ayutthaya period. It plays an important role in many kinds of Thai musical ensembles such as the string ensemble, the string ensemble with Pii Chawa and the Mahori ensemble.