Nuevo Metodo Moreno Cuatro Puertorriqueño. A masterpiece and most popular music book used by the majority of Cuatro beginners. It is utilized in basically every music school throughout Puerto Rico.
The cuatro is the most popular of the Puerto Rican "orquesta jíbara". The Puerto Rican cuatro has ten strings in five courses, tuned in fourths from low to high, with B and E in octaves and A, D and G in unisons: B3 B2, E4 E3, A3 A3, D4 D4, G4 G4.