Karmandir 
About
The Rahu Yantra is the number yantra of Rahu, the first of the two chhaya (shadow) grahas, known from the story of the sharing of amrit. Its nine numbers run from 8 to 16, the Surya square with 7 added to each, so every row, every column and both diagonals add up to 36, with 12 in the middle. In the full Navagraha Yantra, Rahu's square sits in the south-west corner, as the Matsya Purana says. Rahu has no weekday of his own, so families remember him on any day with his verse from the Navagraha Stotram.
Parts of the yantra
Number square: nine cells, written in Devanagari digits in the drawing — top row 13, 8, 15; middle row 14, 12, 10; bottom row 9, 16, 11. Every row, column and diagonal totals 36, and 12 sits in the middle cell. Any two numbers facing each other across the middle always add up to 24. Lines: a gold outer line closes the square and saffron lines divide it into nine cells. Frame: a plain border of three lines around the square, marking the yantra's space.
How to use it
Place the yantra upright on a clean cloth in the puja place. On any day, light a diya, offer a flower and sit quietly facing it. Rest your eyes first on the middle number, 12, then move them through the numbers from 8 up to 16, one cell at a time; this gives the mind one calm thing to follow. Then read Rahu's verse from the Navagraha Stotram (अर्धकायं महावीर्यं…) once, or 11 times. Wipe the yantra with a soft, dry cloth to keep it clean.
अर्धकायं महावीर्यं चन्द्रादित्यविमर्दनम्। सिंहिकागर्भसंभूतं तं राहुं प्रणमाम्यहम्॥
Ardhakayam Mahaviryam Chandraditya Vimardanam. →
Frames differ from print to print: the NCERT figure, for example, draws this square on a shape like a soop (winnowing basket). Many prints use the digits 1, 2, 3 instead of the Devanagari digits used here. The numbers and their places stay the same.
