The Navamsa (D9) Chart, Explained With the Actual Math

If you have ever had a detailed reading, you may have seen the astrologer pull up a second chart after the main one and study it just as carefully. That second chart is almost always the Navamsa, also written as D9.

It gets described in vague terms, "the chart of the soul" or "the marriage chart," and then left there. I would rather show you how it is actually built, because once you see the arithmetic, a lot of the mystery goes away and what remains is more useful.

What a divisional chart is

Your main birth chart, the Rashi chart or D1, places each planet in one of twelve signs. Each sign spans 30 degrees. That is fairly coarse. Two people with the Moon at 2° Taurus and 28° Taurus both have "Moon in Taurus," even though the Moon is in quite different territory.

Divisional charts (vargas) cut each sign into smaller pieces and map each piece to a sign of its own. The D2 cuts each sign in half. The D3 cuts it into thirds. The D9 cuts each sign into nine equal parts, and each part is 3 degrees and 20 minutes wide. The word navamsa literally means "ninth part."

Parashara lists sixteen of these divisional charts. The Navamsa is the one nearly every tradition treats as essential.

How a D9 position is calculated

This is the part most explainers skip. Every sign is divided into nine slices of 3°20'. Which sign the first slice maps to depends on the element of the sign:

• Fire signs (Aries, Leo, Sagittarius) start counting from Aries
• Earth signs (Taurus, Virgo, Capricorn) start from Capricorn
• Air signs (Gemini, Libra, Aquarius) start from Libra
• Water signs (Cancer, Scorpio, Pisces) start from Cancer

From that starting sign, you simply count forward one sign per slice.

Here is a worked example. Say the Moon is at 15° Taurus. Taurus is an earth sign, so we start counting from Capricorn. Now we find which slice 15° falls into:

Slice	Degrees in the sign	Navamsa sign
1	0°00' to 3°20'	Capricorn
2	3°20' to 6°40'	Aquarius
3	6°40' to 10°00'	Pisces
4	10°00' to 13°20'	Aries
5	13°20' to 16°40'	Taurus

15° falls in the fifth slice, so the Moon's Navamsa sign is Taurus. It is in Taurus in the birth chart and in Taurus in the Navamsa as well.

The rule has a nice property. Because Aries, Capricorn, Libra and Cancer are each nine signs apart in sequence, the 108 slices across the zodiac run in one continuous loop, Aries to Pisces, twelve times over. The same 108 slices line up exactly with the 108 padas (quarters) of the 27 nakshatras. So the pada your Moon sits in, which the nakshatra finder shows you, is also its Navamsa slice.

Vargottama: same sign in both charts

What happened to the Moon in that example has a name. When a planet occupies the same sign in the D1 and the D9, it is called Vargottama. It is traditionally read as a strengthening. The planet is consistent across both layers of the chart, and its results tend to come through more cleanly.

Every sign has exactly one Vargottama slice. For movable signs it is the first slice, for fixed signs it is the fifth (the middle), and for dual signs it is the ninth (the last).

Why it is called the marriage chart

Parashara ties the Navamsa closely to the spouse and to dharma. In practice, astrologers read it for two things.

The first is marriage and partnership. The 7th house of the D9, its lord and the state of Venus in the D9 fill in what the birth chart only sketches. A tense 7th house in the D1 that is well supported in the D9 usually reads better than it first looks. If you want to see how this fits into marriage timing, this piece walks through it.

The second is the real strength of a planet. A planet exalted in D1 but debilitated in D9 is often read as promising more than it delivers. A planet debilitated in D1 but strong in D9 tends to improve with age. Many astrologers will not call a planet strong or weak until they have checked it here.

The birth-time problem

The Navamsa is precise, and that precision cuts both ways. Each slice is only 3°20' wide, so the D9 ascendant changes on average about every 13 minutes. A birth time that is off by a quarter of an hour can put the Navamsa lagna in a different sign, which moves every D9 house along with it.

Planets are less sensitive, because they move far more slowly than the ascendant. The Moon moves roughly half a degree an hour, so a planet's D9 sign is usually stable unless it sits right at a slice boundary.

So if your birth time is approximate, trust the D9 planets more than the D9 houses. That is a rule we follow on Astrika too.

See your own

Astrika computes both your D1 and your D9 from Swiss Ephemeris positions using the Lahiri ayanamsa. Generate your chart and compare the two side by side: any planet sitting in the same sign in both is Vargottama, and you now know how to check it by hand.