Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · War Astrology: Yogas, Nakshatras
युद्धजयार्णवः (योगाः नक्षत्राणि)
दशकोटिसहस्राणि अर्बुदं न्यर्बुदं हरेत् ।त्रयोदश च लक्षाणि प्रमाणं कूर्मरूपिणः ।मघादौ कृत्तिकाद्यन्तस्तद्देशान्तः शनिस्थितौ ॥ ९ ॥
In the full Agni Purana this is chapter 123, verse 9.
Ten thousand crore. Take away an arbuda and a nyarbuda. Thirteen lakh more is the size of the one in tortoise form. The stars run from Magha at the start to Krittika at the end. When Saturn stays there, that land meets its end.
Simple meaning: The tortoise figure runs from Magha to Krittika. Saturn there can ruin the land it rules.
राहुचक्रे च सप्तोर्ध्वमधः सप्त च संलिखेत् ।
In the Rahu wheel, seven lines are drawn above and seven below, and the full moon day starts in the south-east.
अमावास्यां वायवे च राहुर्वै तिथिरूपकः ।
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.