Manasara 67.12

67.12

athavā pṛṣṭhamadhye tu sūtra manvanta lambayet
caturdikṣu caturmadhye pañcasūtraṃ pradhānakam

Or else one should drop the line in the center of the back up to fourteen [digits]. / In the four directions, in the center of the four sides, the five lines are primary.