Shula

Shula is the ninth nityayoga, and its name means a spear or a sharp pain. It is one of the inauspicious yogas, associated with conflict, injury, and piercing difficulty, and the panchanga counts it among the configurations to be avoided for auspicious beginnings, especially journeys and ceremonies. Like the others it is derived from the combined longitude of Sun and Moon divided into twenty-seven equal parts. In choosing a muhurta an astrologer sets aside the malefic yogas, and Shula, with its imagery of the spear, is one the tradition treats with caution. These are the conventions of the calendar tradition, which fixes the character of each yoga; the astronomical basis is only the arithmetic of the two lights' summed motion through the month.

Shula is also the name of the trident, trishula, the weapon most closely associated with Shiva in Hindu iconography, though the yoga's own name uses the simpler, unprefixed word for a spear or a piercing pain rather than the specifically three-pronged trident; the two words share a root sense of a piercing point rather than naming identical objects. Classical Indian medicine, Ayurveda, also uses shula as a technical term for a broad category of sharp, stabbing bodily pain, so the yoga's inauspicious association with injury and piercing difficulty draws on a term with an established, non-astrological technical use in the medical literature as well as in general vocabulary.

A yoga is arrived at by addition, which sets it apart from every other reckoning in the almanac. 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. Shula is the arc from 106 degrees 40 minutes to 120 degrees 00 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 Shula is the ninth 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 ninth position, Ashlesha, is where it usually starts.

Shula sits among the nine yogas classed as unfavourable. Nine of twenty seven is a third of the cycle, so an inauspicious yoga is a common event rather than a rare one, and the muhurta literature treats it accordingly: it weighs against a time without ruling it out, and is routinely overridden where the tithi, the nakshatra and the weekday agree.