A History of the Kerala School of Hindu Astronomy (in Perspective) c7.s7.3

c7.s7.3

(b) *Kaṭapayādi notation.* An extremely convenient method of expressing numbers through letters, known as the *Ka-ṭa-pa-yādi* notation, has been extensively used in Kerala from very early times. A legendary author named Vararuci is credited with this innovation and the authorship of the popular collection of *Candra-vākyas* or *Vararuci-vākyas* (‘Moon computation sentences’), composed in this notation. The *Grahcāranibandhana* of Haridatta (A.D. 683) also uses this notation extensively. In this notation, each of the four series of consonants beginning with *k, ṭ, p,* and *y* in the Sanskrit alphabet stands for the digits 1 to 9. In conjunct letters, the value only of the final consonants is to be taken into account. Vowels following the consonants have no value. *n* and *ñ* and the pure vowels stand for zero.