Batak calendar.

12 bamboo slats, 0,8 x 17 cm, attached with twines to a lightweight wooden support (1 slat untied).

Each slat represents a month and is numbered in the upper part with Arabic numerals, each one being divided into 30 days (360-day calendar, compensated every 6 years by an additional month). These calendars, with astrological and prophetic content, were made by priests in North Sumatra.
Prov. [JeanThevenet, lawyer, journalist and member of the Royal Geographical Society of Antwerp, who participated in 1933 in Prince Leopold's scientific expedition to New Guinea].