People have been trying to make sense out of the specifics of the Vedic daśā system forever. Some even advertise that they have done so, but disappoint with, at best, circular answers like “the sky is blue because blue is the wavelength we see when we look at the sky.”

There is a bigger problem, too, which dissuades one from making the effort to figure it out…

Even if one miraculously manages to figure out Viṁśottarī’s logic, it will be nothing short of divine intervention to figure it out in a way that also figures out the several other (and apparently completely different nakṣatra daśā systems). And if an explanation only works on one of the many nakshatra daśā systems, its not really a fully satisfying explanation.

The Basic Idea

The basic idea is just that there should be an “order” in which planets give the results they indicate in a chart. To get that order we just need to define two arrays of info, and one simple variable

1) What is the order?
2) How long does each part of it last?
3) What does it astrologically correlate to?

All “nakṣatra daśā” answer #3 by saying “nakṣatra.” That is almost the only thing they have in common, unfortunately. For the other two, Viṁśottarī has its answers, which are different from Aṣṭottarī, which are different from Ṣodaśottarī, which are different from Dvādaśottarī, etc.

Not Aśvinī

One other thing all the nakṣatra daśā have in common is that none of them start from Aśvinī. This is a strong suggestion that they were developed in the very distant past, before the corruption of the zodiac and the implementation of Aśvinī as the wrong “first” nakṣatra. If they were indeed developed in the very distant past, it could also make sense that any explanations of the thought processes behind developing them had more time to be lost and forgotten.

Perhaps the fact that Viṁśottarī starts from Kṛttikā is part of the reason why it is considered the default daśā system? (Kṛttikā is the true “first” Vedic nakṣatra). Aṣṭottarī also starts from Kṛttikā, and is the “runner-up” to Viṁśottarī in the popularity contest.

The Sun

One other thing they all have in common: they all start their sequence with the Sun. This taunts us to try to make sense of the order, since every sequence, “obviously starts at the obvious start.”

Planetary Orders

All of the systems specify different sequences in which the planets should take center stage in a native’s life. For example,

Viṁśottarī: Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu, Venus.

Aṣṭottarī: Sun, Moon, Mars, Mercury, Saturn, Jupiter, Rahu, Venus (no Ketu)

Ṣodaśottarī: Sun, Mars, Jupiter, Saturn, Ketu, Moon, Mercury, Venus (from Puṣya)

Dvādāśottarī: Sun, Jupiter, Ketu, Mercury, Rahu, Mars, Saturn, Moon (no Venus, from Revatī)

Dvisapati Sama

In this relatively unknown nakshatra dasha system (defined in Parāśara 48.37-39, Sagar Edition) the order of the planets is identical to their normal order – the order we are familiar with: the weekday order. Maybe the name of this daśā also hides a clue?

Dvi: 2.

Sapati: 70.

Dvisapati = 72.

Like all other daśā systems, this one is boringly named by its total year length. It is 72 years long.

But unlike the others, this one has an extra word in its name: sama (“even” / “same”). Does this mean “same as the natural order”? Maybe, but more directly it just indicates that, unlike the rest of the systems, the length of each dasha in this system is the same. Every planet has an equal, 9-year dasha.

Lengths of Periods

Each system has different length, very obviously indicated by its numeric name. Viṁśottarī, 120 years. Aṣṭottarī, 108. Ṣodaśottarī, 106, Dvādāśottarī, 112. Etc.

The rationale of these lengths was revealed by Paraśara. They approximate the maximum duration of a human life.

Every system splits its total length into proportions per planet, and keeps those proportions exactly for determining subperiods withinthose main phases.

However, every system has a different definition of these proportions. None give any reasoning to them.

Conditions…

Parāśara says Viṁśottarī is to be used unless certain conditions are found in a chart. Each non-viṁśottarī system has its own conditions, in which it replaces Viṁśottarī.

• Dvisapati-sama: 1st lord is in the 7th, or the 7th lord is in the 1st.
• Dvādāśottarī: Ascendant Navamsha belongs to Venus
• Ṣodaśottarī: Moon is waning and Ascendant is in lunar hora. Or, Moon is waxing and Ascendant is in solar hora.
• Aṣṭottarī: Rāhu trinal or angular to the 1st lord, but not in the ascendant.

These rules are not very transparent, because it seems easy for many people to have several options that are viable. This may contribute to the popular practice of 99.9% of astrologers: to pretend that Viṁśottarī alone exists.

Conclusion

I feel that Dvisapati-sama provides our best hope for ever making sense out of the values these systems use. Its order is familiar and explanable…

…maybe the order is unchanged (sama) because the durations are equal (sama)?

Or…

…maybe because the length is 72, and that is very similar to the weekdays (of which there are seven)?

The only thing I can think of is that the amount of deviation of the system’s length from a multiple of 7 and/or from sameness in length of the periods, causes a change that affects the order? Maybe the order could be determined by the angle of trajectory for the line in a diagram similar to a Chaldean-order diagram? Maybe the length of the periods could be similarly derived from the deviation in the total length?

Maybe in the future, I will try to follow up on this clue. Meanwhile, maybe the esteemed reader can take up the cause?