A Batak shaman’s calendar, “porhalaan”.

[Northern Sumatra, twentieth century]. Comprised of twelve bamboo slats incised with Batak script, suspended by twine from a bone finial incised with shamanic symbols; dimensions 180 x 110 mm; intact, darkened patina overall.

A Batak datu or shaman’s calendar, “porhalaan”, used not for determining the date but rather auspicious times for rituals. Each of the bamboo slats represents one month, with incisions marking off 30 days; each slat has Batak script incised along its length, marking the days. (The Batak script probably evolved around 1300 CE and is derived from the ancient Brahmi script of India). The days on the individual slats are read from top to bottom, while the entire calendar is read from right to left. The convex surface of the animal bone finial is also incised with four shamanic motifs and two sequences of Batak script.