Tibetan calendar

The second cycle was derived from China and was called Drukchu kor (Tibetan: དྲུག་ཅུ་སྐོར།, Wylie: drug cu skor, Sanskrit Vrhaspati).

The structure of the drukchu kor was as follows: Each year is associated with an animal and an element, similar to the Chinese zodiac.

On Tibetan banknotes from the first half of the 20th century cardinal numbers can be seen, with year 1 in 255 CE, which is a reference to the legendary 28th Emperor of Tibet, Thothori Nyantsen.

In this era the first year is 127 BCE, dated to the legendary progenitor of the Yarlung dynasty, Nyatri Tsenpo.

The lengths of such lunar days vary considerably due to variations in the movements of the Moon and Sun.

In consequence, a Tibetan calendar month (zla ba) comprises 29 or 30 natural days.

The days of the week (Tibetan: གཟའ, Wylie: gza') are named for astronomical objects.

[7] Nyima "Sun", Dawa "Moon" and Lhakpa "Mercury" are common personal names for people born on Sunday, Monday or Wednesday respectively.

kar rtsis, that divided the days into rhythms defined by the elements and the constellations,[8] and later used a Chinese astrological system, Tib.

byung rtsis, which focuses on twelve animals and the five elements to describe patterns of events.

The Indian and Chinese systems were joined by the Buddha's teachings found within the Sutra Avatamsakra and the Tantra Kalachakra to develop the Tibetan astrological calendar.

The translation of the Kalachakra Tantra in the late 11th century CE marked the beginning of a change of Tibet's calendar.

This tantra references the Indian astronomical calendar system with its calculations that follow the progression of the constellations - the five planets, and the sun and moon eclipses.

The Tsurluk calendar is still overseen by Tsipa Gelek Dhargay, at the 17th Karmapa, Ogyen Trinley Dorje's seat in Rumtek, Sikkim, India.