A lot of Hindu calendars do this. They use śukla and kr̥ṣṇa pakṣa (waxing and waning phases respectively). Days are numbered 0-14 with 0 referring to the full/n

A lot of Hindu calendars do this. They use śukla and kr̥ṣṇa pakṣa (waxing and waning phases respectively). Days are numbered 0-14 with 0 referring to the full/new moon. Problem is each regional calendar is slightly different. And days might repeat.