Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
जन्मभादासुताष्टांकांत्यायेष्विष्टो भृगोःसुतः ।चेन्न विद्धोऽष्टसप्तांगम् खांकाद्यायारिरामगैः ॥ २७६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 276.
Venus, Bhrigu's son, is good from the birth sign in the 1st to the 5th. It is also good in the 8th, 9th, 12th and 11th. That holds if planets do not block it. They block from the 8th, 7th, 1st, 10th, 9th, 'adya', 11th, 6th and 3rd. (Our text is unclear here: the blocking place 'adya'.)
Simple meaning: Venus is good in most places from the birth sign, unless planets in blocking places stop it.
न ददाति शुभं किंचिद्गोचरे वेधसंयुते ।
A blocked planet in transit gives nothing good, so check the blocking first.
वामभेदविधानेन दुष्टोऽपि स्याच्छुभङ्करः ।
Reverse blocking can turn a bad planet good. Looks of good or bad planets reverse the result.
निष्फलौ तौ ग्रहौ स्वेन शत्रुणा च विलोकितौ ।
A planet seen by its enemy, or in its low or enemy sign, gives no result.