Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · War Astrology: Yogas, Nakshatras
युद्धजयार्णवः (योगाः नक्षत्राणि)
अमावास्यां वायवे च राहुर्वै तिथिरूपकः ।रकारं दक्षभागे तु हकारं वायवे लिखेत् ॥ ११ ॥
In the full Agni Purana this is chapter 123, verse 11.
The new moon day is in the north-west. Rahu is of the form of the tithi (moon day). Write the letter ra on the south side and the letter ha in the north-west.
Simple meaning: The new moon day is in the north-west. Write ra on the south side and ha in the north-west.
प्रतिपदादौ ककारादीन्सकारं नैर्ऋते पुनः ।
Letters are written from ka, starting from the first moon day. Defeat comes at Rahu's mouth.
विष्टिरग्नौ पौर्णमास्यां करोलीन्द्रे तृतीयकम् ।
Vishti moves by moon day: south-east on the full moon, east on the third, south on the seventh, north on the tenth.
चतुर्दश्यां तु वायव्ये चतुर्थ्यां वरुणाश्रये ।
On the fourteenth she is north-west, on the fourth west and on the bright eighth south. Avoid the eleventh.