The mapping of a Rasi sign into the Navamsa (D9) Chart involves dividing each 30-degree zodiac sign into nine equal segments of 3 degrees and 20 minutes (3°20′) each.

The starting point of the count in the Navamsa depends on the modality (nature) of the Rasi sign in the birth chart: [1]

• Movable (Chara) Signs (Aries, Cancer, Libra, Capricorn): Counting for the first Navamsa starts from the sign itself.
• Fixed (Sthira) Signs (Taurus, Leo, Scorpio, Aquarius): Counting for the first Navamsa starts from the 9th sign from it.
• Dual (Ubhaya) Signs (Gemini, Virgo, Sagittarius, Pisces): Counting for the first Navamsa starts from the 5th sign from it

If a planet is in Aries (Movable sign) at 12°15′, it falls in the 4th Navamsa part (10°00′ to 13°20′).

EXAMPLE CHART:

When the lagna rising is Leo in natal chart in the 13degree06seconds and Leo being a fixed sign it will be mapped to the 9th sign from the fixed sign and the lagna being in 13degrees then the mapping is as follows:

Aries 0:00 to 3degree20seconds

Taurus 3degrees20seconds till 6degrees40seconds

Gemini 6degrees40seconds till 10degrees0seconds

Cancer 10degrees0seconds till 13degrees20 seconds

As the lagna is of 13 degrees the lagna of the Navamsa will be placed in the sign of CANCER

In the same way for Movable sign the first Navamsa will start from the sign itself

For Dual sign the first Navamsa will start from the 5th sign