Vriddhi

Vriddhi is the eleventh nityayoga, and its name means growth, increase, and prosperity. It is one of the auspicious yogas, favourable for undertakings meant to expand and flourish, new ventures, investments, and matters of increase. Like every nityayoga it is found from the combined longitude of Sun and Moon divided into twenty-seven equal parts, advancing through the month. In the panchanga it contributes its favourable, expansive quality to the reckoning of an auspicious time, one of the five daily limbs the tradition weighs. These are the conventions of the calendar tradition, in which a benefic yoga such as Vriddhi commends a moment for growth; the astronomical basis remains the simple arithmetic of the two luminaries' summed longitude.

Vriddhi, growth or increase, is also a specific technical term in Sanskrit grammar, naming one of the two regular categories of vowel strengthening, vriddhi and guna, that Panini's grammatical system uses to describe how a root vowel changes in forming derived words, so the same word that names this auspicious yoga also names a foundational concept in the analysis of the Sanskrit language itself. The yoga's calendrical sense of growth and prosperity and the grammatical sense of a strengthened vowel are independent developments of the same basic root meaning, augmentation or increase, rather than one being derived from the other.

Of the five limbs of the panchanga the yoga is the most purely arithmetical, and the only one a person standing outside at night could never read off the sky. Where the tithi measures the Moon's separation FROM the Sun, the yoga measures the two longitudes ADDED together, and cuts the resulting circle into twenty seven equal arcs of thirteen degrees twenty minutes. Vriddhi is the arc from 133 degrees 20 minutes to 146 degrees 40 minutes of that sum. The sum climbs at roughly fourteen degrees ten minutes a day, so a yoga runs about twenty two and a half hours on average, a little shorter than a tithi, and like a tithi it can be skipped between two sunrises or carried across two of them.

The twenty seven arcs are the same width as the twenty seven nakshatras, and Vriddhi is the eleventh arc of the grid in both schemes, which is why the two are often tabulated side by side. They are not the same thing and share nothing but their arithmetic: a nakshatra is a segment of the sky the Moon is physically standing in, while a yoga is a number derived from two positions and belongs to no part of the sky at all. Reading a yoga as a star group is the commonest confusion the term invites, and the shared name of the eleventh position, Purva Phalguni, is where it usually starts.

Vriddhi sits among the eighteen yogas classed as favourable. That count matters more than it looks: with eighteen of twenty seven benign, the yoga is a weak filter on its own, and the classical muhurta writers use it as a tie breaker between candidate times rather than as a reason to reject one. A day is not made auspicious by its yoga alone.