The posture conditions your meditation. Without good posture, there isn´t good meditation. Sit inappropriately and soon you´ll begin to feel discomfort in your knees, hips, back or neck. After a while, the discomfort´ll give way to pain and you´ll find it increasingly uncomfortable to remain seated. This physical discomfort´ll bring mental agitation and your meditation session´ll become a little hell, so that this doesn´t happen to you have the Zafu Hamana´ll make your meditation sessions a delight for the senses.
