Two Sinhala numeral traditions
Harsha’s research, begun in 2007 and published in the 2009 book Numeration in the Sinhala Language, drew on rock inscriptions, ola-leaf manuscripts, early Dutch and Portuguese publications and material in Sri Lankan museum collections. It distinguishes two related but functionally different numeral systems.
An additive numeral system used by the Kandyan royal court and visible in the 1815 Kandyan Convention. It had signs for units and powers such as 10, 100 and 1,000, but no zero.
A decimal place-value system used especially in astrology and ephemerides. It employed a zero placeholder and remained in practical use in horoscope calculation.
Both traditions are traced to Brahmi numeral forms recorded in Sri Lanka. Sinhala Illakkam retained an additive structure, while Lith Illakkam developed decimal notation.
Sinhala Illakkam and Lith Illakkam were encoded in Unicode, preserving the ability to represent both historical systems digitally.
The Sinhala zero
Ola manuscripts on astrology show a zero placeholder associated with the hal lakuna or halanta. The research argues that Sri Lankan astrologers used place-value notation in addition, subtraction, multiplication and division by at least the early eighteenth century. It also explores an earlier hypothesis: that the nullifying function of the halanta in Sinhala writing and the placeholder function of zero may reflect a related conceptual history. The Menikdena brick marks described in the research are presented as suggestive evidence requiring further archaeological study—not as a settled identification.
The distinction between śūnya as emptiness and binduwa as a numerical zero becomes especially important in the Pujavaliya. The text appears to use the latter in a specifically quantitative comparison, supporting the argument that zero was understood independently as a number.