Karmandir 
About
The Ketu Yantra is the number yantra of Ketu, the second chhaya (shadow) graha; the word ketu also means a flag. Its nine numbers run from 9 to 17, the Surya square with 8 added to each, so every row, every column and both diagonals add up to 39, with 13 in the middle. It is the last of the nine graha squares. In the full Navagraha Yantra, Ketu's square sits in the north-west corner, as the Matsya Purana says. Ketu 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 14, 9, 16; middle row 15, 13, 11; bottom row 10, 17, 12. Every row, column and diagonal totals 39, and 13 sits in the middle cell. Any two numbers facing each other across the middle always add up to 26. 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, 13, then move them through the numbers from 9 up to 17, one cell at a time; this gives the mind one calm thing to follow. Then read Ketu's verse from the Navagraha Stotram (पलाशपुष्पसंकाशं…) once, or 11 times. Wipe the yantra with a soft, dry cloth to keep it clean.
पलाशपुष्पसंकाशं तारकाग्रहमस्तकम्। रौद्रं रौद्रात्मकं घोरं तं केतुं प्रणमाम्यहम्॥
Palasha Pushpa Sankasham Taraka Graha Mastakam. →
Frames differ from print to print: the NCERT figure, for example, draws this square on a flag shape. Many prints use the digits 1, 2, 3 instead of the Devanagari digits used here. The numbers and their places stay the same.
