Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
तत्तत्सप्तमनीचानि प्राङ्मध्यांत्यांशकाः क्रमात् ।वर्गोत्तमाश्चराधेषु भावाद्वादश मूर्तिमान् ॥ ९ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 9.
The 7th sign from each of those is its low point. In moving, fixed and dual signs, take the first, middle and last navamsha (one-ninth part of a sign) in turn. These are vargottama (same sign in the chart and its navamsha). There are twelve bhava (house) places. The first is the body.
Simple meaning: Each planet is weakest in the sign opposite its strong sign. The first house is the body.
सिंहोक्षाविस्रश्चतौलिकुंभाः सूर्यात्रिकोणभम् ।
Sun, Moon and Mars have strong parts in Leo, Taurus and Aries. The 5th and 9th are luck houses.
रिःफाष्टषट्कं त्रिकभं केंद्रं प्राक्तुर्यसप्तखम् ।
The 6th, 8th and 12th are bad places. The 1st, 4th, 7th and 10th are corner houses.
केंद्रात्परं पणफरमापोक्लिममतः परम् ।
After the corner houses come the succeeding houses, then the falling houses. The signs also have colours, from red upward.