大唐西域記 2.4.1

2.4.1

Although the revolution of the Yin and Yang principles and the successive mansions of the sun and moon be called by names different from ours, yet the seasons are the same; the names of the months are derived from the position (of the moon in respect) of the asterisms. The shortest portion of time is called a t'sa-na (kshana); 120 kshanas make a ta-t'sa-na (takshana); 60 of these make a la-fo (lava); 30 of these make a mau-hu-li-to (muhurta); five of these make "a period of time" (kâla); six of these make a day and night (ahôrâtra); but commonly the day and night are divided into eight kâlas. The period from the new moon till full moon is called the white division (Sukla-paksha) of the month; the period from the full moon till the disappearance (of the light) is called the dark portion (Krishna-paksha). The dark portion comprises fourteen or fifteen days, because the month is sometimes long and sometimes short. The preceding dark portion and the following light portion together form a month; six months form a "march" (hing, S. ayana). The sun when it moves within (the equator) is said to be on its northward march; when it moves without (the equator) it is on its southern march. These two periods form a year (vatsara).