Krishna Shashthi, Sacred to Skanda

Krishna Shashthi is the twenty-first tithi overall, the sixth day of the dark fortnight, sharing the character of the sixth tithi and its dedication to Kartikeya or Skanda, the war-god. In the fivefold grouping it is a Nanda or joyful tithi. The waning Moon by this day is near its last quarter, rising around midnight. While the great Skanda festivals fall in the bright fortnight, the sixth tithi of the dark half carries his associations too, and regional observances vary. These are the conventions of the calendar and festival tradition, in which the character of a tithi follows its number across both fortnights while its auspicious weight is modulated by whether the Moon is waxing or waning.

Because the great Skanda festivals cluster in the bright fortnight, principally the six-day cycle culminating in Skanda Shashthi itself, the dark-fortnight Shashthi has comparatively little independent festival literature of its own, and its main significance in most panchangas is simply as the sixth tithi of the waning half carrying the standard Nanda classification and Kartikeya's general association rather than any specific named observance. This asymmetry, where one fortnight's instance of a tithi accumulates rich festival tradition while the other largely does not, recurs across several numbered tithis in this list and reflects the historical accident of which month and fortnight particular festivals happened to become fixed to, rather than any rule governing bright versus dark observance generally.