The Vimshottari Dasha, aka Planetary Period System, is an ancient, much venerated technique used to make predictions in Vedic Astrology natal chart analysis. It is comprised of 9 ‘major periods’ (dashas) consisting of between 6 and 20 years, giving a total of 120 years to the whole cycle. The sequence of periods is the same for everyone, but where you are on the sequence is calculated from the exact placement of the Moon at birth, plus the number of elapsed years we are considering. (The calculations are made nowadays using the astrology software written for the personal computer.) Each of the major periods has a planetary ruler whose natural qualities define the period. During any particular planet’s major period, the karma associated with the houses of the natal chart that the period ruler owns by way of its signs will be activated. That karma will be expressed through the venue of the house that the period ruler occupies. 

Within each major period there are sub-periods: the same sequence of nine planetary rulers as the major periods, in the same proportion to each other, but now compressed into the number of years of the current major period. Depending on the how long the major period is, the sub-periods are from a few months up to 3 years or so in duration. The sub-period rulers, in the same manner as the major periods, will each activate particular parts of the birth chart karma by way of the signs/ houses ruled and the planet’s placement. 

A period ruler in its own or favorable sign with a benefic planet’s aspect or association is more able to express itself and deliver on its promise than a planet in an unfavorable sign aspected by a malefic planet. Certain sectors in the chart, namely the Kendra houses (1st, 4th, 7th, 10th) are more conducive to manifesting events in one’s life, as compared to more static houses. A period ruler that occupies one of the Dusthana houses, i.e., houses that indicate detrimental events (6th, 8th, 12th), is more likely to produce trouble during its period. There are also special yogas, such as the Vipreet yoga, which can counteract the effects of a planet in a detrimental house.  

In order to know if its potentials will manifest or not, it is necessary to evaluate the strength of the period’s planetary ruler. A planet that is weak in a chart, due to its sign or house position, or due to being overwhelmed by a stronger planet, or because its dispositor is weak, will be less likely to produce significant events in one’s life. On the other hand, a planet that has strength in the natal chart can be counted on to manifest its promise during its period. This can be for good or for ill. If a planet is strong, rules beneficial houses, and is well placed, it will produce positive events, whereas a planet that is determined to be negative for one’s life and simultaneously strong, will cause maximum trouble during its period. On the other hand, a positive but weak period ruler will produce hope but no events; a negative planet that is weak will produce anxiety but no actual outcomes. 

To understand the structure of the Planetary Period System, a useful metaphor would be to think of the major period as the background of your painting, which goes on for several to many years. The sub-period would then be the foreground of your painting, therefore closer to you, and changing more frequently. The sub-period functions within the overall context of the major period, while the major period has to express its significations through the agency of the sub-period.

A critical concept for making predictions with the planetary period system is the relationship between the major period and the sub-period planets as shown by their positions in the natal chart. If the ruler of the sub-period is a “friend” of the major period planet, and is well placed in the chart in its own or friendly sign, then the promise of the major period planet can be delivered. On the other hand, if the sub-period planet is an enemy of the major period planet, and/or is in trouble in the chart such as being in a dusthana house or in an incompatible sign, or being overwhelmed by another planet, then the promise of the major period planet cannot be fulfilled. 

Another aspect of the relationship between the major period and sub-period rulers is their relative positions in the natal chart. Using the major period planet as the starting point, count the number of houses to the sub-period ruler. If the sub-period ruler is in the 5th or 9th house from the major period ruler, the events during that sub-period will manifest smoothly without trouble. If on the other hand, the sub-period ruler is in the 6th, 8th, or 12th position relative to the major period ruler, the events during that sub-period will manifest with difficulty, or be attended with some loss or unhappiness. 

The type of events that occur during any sub-period will be in line with the natural significations of the ruling planet, and according to the meanings of the houses activated in the natal chart. Combinations of major and sub-period planets that reinforce their natural qualities along with their house meanings are much more likely to result in events, whereas contradictory meanings often don’t show up as events at all, i.e., the significations can cancel each other out, resulting in no outcome. 

There are many different techniques, rules, formulas, etc. in Vedic Astrology for predicting the future. What has been discussed here is just a brief overview of one such technique. The Vimshottari Dasha system has proved itself over many centuries of use to be accurate and dependable, and is therefore one of the most popular methods for looking into the future. Learning how to apply this formula to make reliable predictions for an individual’s natal chart is an important tool in the Vedic Astrologer’s toolkit.