Krishna Dashami and the Thinning Moon

Krishna Dashami is the twenty-fifth tithi overall, the tenth day of the dark fortnight, sharing the character of the tenth tithi, whose presiding deity is traditionally Yama, lord of dharma. It is a Purna or full tithi in the fivefold grouping and so read as relatively stable. The waning Moon is now a slim crescent in the pre-dawn sky, drawing close to the Sun. The panchanga reads the tenth tithi of either fortnight as generally favourable, though the dark fortnight's diminishing light tempers its use for auspicious beginnings. These are the conventions of the Hindu luni-solar calendar, which counts thirty tithis to the month and gives each a character partly from its number and partly from its paksha.

Yama's connection to the tenth tithi, carried into the waning fortnight without the countervailing triumph of Vijayadashami that colours the bright-fortnight Dashami so strongly, leaves the dark Dashami read more straightforwardly through Yama's role as upholder of dharma and order rather than through any specific festival narrative, since no major all-India observance is fixed to this particular waning tenth day. As a Purna tithi it retains its generally stable character within the dark fortnight even so, one of several waning-fortnight tithis where the fivefold classification's inherent favourability partially offsets the general caution the tradition applies to the diminishing half of the month.