Shashthi, Sacred to Skanda

Shashthi is the sixth tithi of the bright fortnight, a Nanda or joyful tithi in the fivefold grouping. Its presiding deity is Kartikeya, also called Skanda or Murugan, the war-god and son of Shiva, and the sixth tithi is his throughout the calendar. Skanda Shashthi, in the bright fortnight of the autumn month, is his major festival, especially in the Tamil tradition where Murugan is a central deity; the day commemorates his victory over the demon Surapadman. Around the sixth tithi the waxing Moon approaches its first quarter. In the panchanga the day is read as favourable, and its devotional weight rests on Skanda rather than on the general classification. These attributions belong to the calendar and festival tradition.

Murugan's especially strong identification with the sixth tithi in Tamil Shaiva tradition runs deep enough that Skanda Shashthi is observed as a six-day cycle of fasting culminating on the tithi itself, commemorating the god's mythological six-day war against the demon Surapadman before his final victory, so the festival's structure directly echoes the number that names the tithi. Because Kartikeya, Skanda and Murugan are regionally distinct emphases of what the wider Puranic tradition treats as a single deity, the sixth tithi's devotional colouring can differ noticeably between a South Indian and a North Indian panchanga even though the underlying tithi arithmetic, the Moon's twelve-degree gain on the Sun, is identical everywhere.