They are related to the bandurria and mandolin. Dadap is also the author of the book "Complete Method for the Virtuoso Bandurria". Musical instruments like lute and bandurria are also used. The Spanish bandurria, still used today, is a similar instrument. In Lima, Peru, harp and bandurria duos were common in the early 20th century. Williamson's instrument featured a basic guitar fingerboard with a bandurria attached and sympathetic resonating strings. Jota instruments include the castanets, guitar, bandurria, tambourines and sometimes the flute. The modern bandurria has 12 strings (6 pairs). South of the city of Huacho is located a large archaeological site of Bandurria, Peru. There are also many different varieties of bandurria in South America, especially Peru and Bolivia. The Filipino bandurria is used in an orchestra of plucked string instruments called rondalla. The same thing also happened when he started formally studied Bandurria under Jose Silos. In its Spanish form the bandurria may have resembled the rebec. While the Spanish guitar is widely played, so too is the Spanish-in-origin bandurria. During the Baroque period the bandurria had 10 strings (5 pairs).