Wikipedia
The kutiyapi, or kudyapi, is an indianized Filipino two-stringed, fretted boat- lute. It is the only stringed instrument among the Maguindanao people, and one of several among other groups such as the Maranao and Manobo. It is four to six feet long with nine frets made of hardened beeswax. The instrument is carved out of solid soft wood such as that from the jackfruit tree.
Common to all kudyapi instruments, a constant drone is played with one string while the other, an octave above the drone, plays the melody with a kebit or rattan pluck (commonly made from plastic nowadays). This feature, which is also common to other related Southeast Asian "boat lutes", which were influenced by varying degrees by Indian classical music concepts of melody and scale via Maritime Southeast Asia. (See Indosphere for more information on historic Indian cultural influence in Southeast Asia.)