Karmandir 
About
The Shani Yantra is the number yantra of Shani dev, the son of Surya and Chhaya, whose name Shanaishchar means "the one who moves slowly". Its nine numbers run from 7 to 15, the Surya square with 6 added to each, so every row, every column and both diagonals add up to 33, with 11 in the middle. In the full Navagraha Yantra, Shani's square sits on the west side, the place the Matsya Purana gives him. Families keep it in the puja place and remember Shani dev on Saturdays with his verse from the Navagraha Stotram.
Parts of the yantra
Number square: nine cells, written in Devanagari digits in the drawing — top row 12, 7, 14; middle row 13, 11, 9; bottom row 8, 15, 10. Every row, column and diagonal totals 33, and 11 sits in the middle cell. Any two numbers facing each other across the middle always add up to 22. 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 a Saturday, or on any day, light a diya, offer a flower and sit quietly facing it. Rest your eyes first on the middle number, 11, then move them through the numbers from 7 up to 15, one cell at a time; this gives the mind one calm thing to follow. Then read Shani dev's verse from the Navagraha Stotram (नीलांजनसमाभासं…) once, or 11 times. Wipe the yantra with a soft, dry cloth to keep it clean.
नीलांजनसमाभासं रविपुत्रं यमाग्रजम्। छायामार्तण्डसंभूतं तं नमामि शनैश्चरम्॥
Nilanjana Samabhasam Raviputram Yamagrajam. →
Frames differ from print to print: the NCERT figure, for example, draws this square inside a plain square frame. Many prints use the digits 1, 2, 3 instead of the Devanagari digits used here. The numbers and their places stay the same.
