The Navamsha chart, D-9, is the sixth of the sixteen divisional charts and, after the Rashi itself, the most heavily weighted in jyotisha. It is formed by dividing each sign into nine parts of three degrees twenty minutes, the width of a single nakshatra quarter. It signifies the spouse, marriage, dharma, and the inner strength or ripened fruit of the nativity. Astrologers routinely read the D-1 and D-9 side by side, holding that a planet strong in the Rashi but weak in the Navamsha lacks lasting substance, and vice versa. The Navamsha is treated as revealing the deeper trajectory of the life. These are the interpretive conventions of the tradition; the chart is a harmonic subdivision drawn from the same planetary longitudes as the birth chart.
Parashara's rule assigns the starting point by modality rather than by odd and even parity: in a movable sign, Aries, Cancer, Libra or Capricorn, the nine navamsha divisions are counted from the sign itself; in a fixed sign, Taurus, Leo, Scorpio or Aquarius, the count begins instead from the ninth sign onward; and in a dual sign, Gemini, Virgo, Sagittarius or Pisces, from the fifth sign onward. Because nine navamshas exactly complete three full trips around the twelve-sign zodiac beginning from any of these three starting points, every sign of a given modality always begins its own navamsha count from the same modality-linked point, a structural neatness the tradition treats as part of the chart's special status alongside the D-1.