# The nine conditional nakshatra dashas — sourced

Reference chart: 15 Sep 1980, 07:30:00, TZ +5:30, 72E35 23N02.
Moon 210.683172° — Visakha, 0.80124 of the way through.
Lagna 162.659094° — Virgo.

Every one of the nine was listed as blocked on "the year per lord and the
starting nakshatra". The application supplies both, and it supplies something
the catalogue had not even asked for: **it states each dasha's applicability
condition in the panel title**. That is the part that makes a *conditional*
dasha conditional, and we had no source for any of it.

## The nine

| Dasha | Total | Applicable when | Lords and years, in cycle order |
|---|---|---|---|
| Ashtottari | 108 | (title gives none — it is offered unconditionally) | Ma 8, Me 17, Sa 10, Ju 19, Ra 12, Ve 21, Su 6, Mo 15 |
| Dwi-saptati sama | 72 | lagna lord is in the 7th, or the 7th lord is in lagna | Su 9, Mo 9, Ma 9, Me 9, Ju 9, Ve 9, Sa 9, Ra 9 |
| Shat-trimsa sama | 36 | daytime birth in Sun's hora, or night-time birth in Moon's hora | Sa 6, Ve 7, Ra 8, Mo 1, Su 2, Ju 3, Ma 4, Me 5 |
| Dwadasottari | 112 | lagna is in a Venusian amsa | Me 13, Ra 15, Ma 17, Sa 19, Mo 21, Su 7, Ju 9, Ke 11 |
| Chaturaseeti sama | 84 | the 10th lord is in the 10th | Mo 12, Ma 12, Me 12, Ju 12, Ve 12, Sa 12, Su 12 |
| Sataabdika | 100 | lagna is vargottama | Ve 10, Me 10, Ju 20, Ma 20, Sa 30, Su 5, Mo 5 |
| Shodasottari | 116 | lagna in Moon's hora in Krishna paksha, or in Sun's hora in Sukla paksha | Su 11, Ma 12, Ju 13, Sa 14, Ke 15, Mo 16, Me 17, Ve 18 |
| Panchottari | 105 | lagna is in Cancer in both rasi and dwadasamsa | Mo 17, Ju 18, Su 12, Me 13, Sa 14, Ma 15, Ve 16 |
| Shashti-hayani | 60 | the Sun is in lagna | Me 6, Ve 6, Sa 6, Ra 6, Ju 10, Su 10, Ma 10, Mo 6 |

Every total is exactly the number the dasha is named for — 72, 36, 112, 84,
100, 116, 105, 60, 108 — which is the arithmetic check that the years were read
off correctly.

Note that two of the nine use **Ketu** (Dwadasottari, Shodasottari) and two use
**Rahu** (Dwi-saptati, Shashti-hayani), and three use neither. A nine-lord
Vimsottari intuition would get all of these wrong.

Note also that three of the nine are *sama* — equal-period — dashas, and the
equal period differs: 9 years over 8 lords, 12 over 7, and Shat-trimsa is not
sama at all despite sitting beside them in the menu.

## The observed periods, which are the acceptance tests

These are what our implementation must reproduce for this chart. The starting
lord and the first period's start date together pin both the nakshatra-to-lord
map and the balance formula, so a candidate rule either reproduces them or it
does not.

    Ashtottari        Mars   from 1973-02-04 13:54:06, 8y
    Dwi-saptati sama  Sun    from 1973-06-28 08:31:15, 9y
    Shat-trimsa sama  Saturn from 1975-11-24 19:10:48, 6y
    Dwadasottari      Merc   from 1970-04-13 00:27:30, 13y
    Chaturaseeti sama Moon   from 1971-01-31 16:08:11, 12y
    Sataabdika        Venus  from 1972-09-10 16:27:45, 10y
    Shodasottari      Sun    from 1971-11-22 13:39:16, 11y
    Panchottari       Moon   from 1967-01-29 11:05:22, 17y
    Shashti-hayani    Merc   from 1977-02-04 14:39:51, 6y

## Method note — why this is a test, not a transcription

The nakshatra-to-starting-lord map and the balance formula are classical and
documented; what we lacked was the years, the lord order, the conditions, and
any way to check. We now have all four. So each dasha is implemented from the
classical rule and then *required* to reproduce the start date above to the
minute. A rule that produces the right lord but the wrong date is wrong, and
with the date to four-decimal precision there is nowhere for a wrong rule to
hide.

Worth recording: for Ashtottari, the elapsed fraction of Mars's period at birth
is 0.9513, while the Moon's elapsed fraction of Visakha is 0.80124. The two are
not equal, so the balance is **not** the nakshatra fraction — it is the fraction
elapsed through a *group* of nakshatras assigned to that lord. (3 + 0.80124)/4
= 0.9503 is close but not exact, so the group is four nakshatras wide but the
mapping is not a plain linear one. That discrepancy is precisely the kind of
thing only a measured start date exposes.

The panel header also states the year definition in force: **true sidereal solar
years**, started from the Moon. That is a preference, and it changes every date
above, so it travels with these figures.