5. The Burmese calendar is essentially a Buddhist one, but the methods of computing it are derived from Hindu books. A few words about the Hindu calendar are therefore necessary.
6. In paragraph 17 of "The Indian Calendar," by Sewell and Dikshit, is a list of some of the best-known Hindu works on astronomy. The length of the year is differently estimated in different works. The principal ones which seem to have been used in Burma are the Original Surya Siddhanta and the present Surya Siddhanta. The length of the year as given in these two is respectively:—
| Original | . . . | 365 days, 6 hours, 12 minutes, 36 seconds. |
| Present | . . . | 365 days, 6 hours, 12 minutes, 36.56 seconds. |
7. Sewell and Dikshit show (at paragraphs 47 and 52) that the Hindus formerly reckoned by mean months and years, but at present by apparent months, while both mean and apparent years are used indifferent parts of India. The change from mean to apparent reckoning is supposed to have commenced about A. D. 1040, as it is enjoined in a passage in the Siddhanta Sekhara by the celebrated astronomer Sripati, written in or about that year.
8. The Hindus insert an intercalary month at any time of year, as soon as the accumulated fractions amount to one month. In Burma, as we shall see, this is not so. The intercalary month is always inserted at the same time of year, in Burma proper after the summer solstice, in Arakan after the vernal equinox.
9. Burmese astronomers use the Hindu Kali Yug, which commenced in 3102 B. C. (Sewell and Dikshit, page 16).
Gautama Buddha’s grandfather, King Einzana, is said to have started a new era in 691 B. C.
The Religious Era dates from 543 B. C., the year in which Gautama is supposed to have attained Nirvana.
In A. D. 78-9 King Thamondarit of Prome is said to have started another, identical with the Indian Saka era.
In A. D. 638-9 the era now in common use was started simultaneously, in Burma by King Poppasaw of Pagan and in Arakan by King Thareyarenu of Dinyawadi dynasty. The same era is current in Chittagong under the name of Magi-San. (Sewell and Dikshit, paragraph 71 and table III).
10. So far as I am aware, no record is extant of any calendars as actually observed either in Burma or in Arakan earlier than the year 1100 of Poppasaw’s era (A. D. 1738). Mr. Htoon Chan, B. A., B. L., of Akyab, in his book The Arakanese Calendar, published in 1905, gives the elements of the luni-solar calendar of Arakan for 2,000 years of the current era (A. D. 639 to 2638), but he states that these were compiled during the reign of King Na-ra-a-pa-ya
