Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 3 · Dashas, Yogas, Placements
जातकम् २
अन्योन्यकारकास्ते स्युः कर्मगस्तु विशेषतः ।शुभं वर्गोत्तमे जन्म वेसिस्थाने वसद्गृहैः ॥ २७३ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 273.
They become each other's karaka (the planet that stands for a thing), most of all the one in the 10th. Birth in vargottama (same sign in the chart and its navamsha) is good. So is birth with good planets in the vesi (the sign after the Sun's sign) place.
Simple meaning: Strong planets in corner houses help each other. Birth in a vargottama sign is good.
अशून्येषु च केंद्रेषु कारकाख्यगृहेषु च ।
Full corner houses and karaka planets help. Jupiter and the Moon-sign and lagna lords there give moderate comfort.
पृष्ठोभवकोदपर्क्षस्थितास्त्वंत्यांतरादिषु ।
Sun and Mars act early in a dasha, Venus and Jupiter in the middle.
चंद्रार्की फलदावंत्ये सदा ज्ञः फलदायकः ।
The Moon and Saturn act late in a dasha. Mercury acts all the time.