Vishkambha is the first of the twenty-seven nityayogas, one of the five limbs of the Hindu daily almanac, the panchanga. A nityayoga is not a physical configuration but an arithmetic one: it is found by adding the longitudes of the Sun and Moon and dividing the total into twenty-seven equal parts, so the yoga advances as the two lights separate. Its name means support or a prop, but in the traditional reckoning of auspicious and inauspicious yogas Vishkambha is classed as inauspicious, associated with obstruction. The panchanga therefore counts it among the yogas to be avoided for beginning important undertakings. These are the conventions of the calendar tradition; the astronomical basis is simply the combined motion of Sun and Moon, whose summed longitude sweeps through the twenty-seven yogas over the course of the lunar month.
The Surya Siddhanta, an astronomical treatise of uncertain original authorship generally dated to around the fourth or fifth century CE and substantially revised by roughly the eighth, is the classical source most often cited for the twenty-seven-fold yoga scheme and its method of calculation, which is why the nityayogas are sometimes called the Surya Siddhanta yogas in Sanskrit astronomical literature. Some later compilers also give Vishkambha a presiding rulership under Yama, the god of death and dharma, and the planet Shani, Saturn, the same pairing given to the inauspicious Vishti karana, which if followed consistently would tie the harshest karana and the first yoga to the same governing pair. The word vishkambha also has a distinct secondary sense in Sanskrit geometry, a diameter or supporting cross-beam, related to but separate from the astrological name.