THIS SUTRA, under the title of MAHA-PRAJNA-PARAMITA-HRIDAYA, formed another section of the great MAHA-PRAJNA-PARAMITA SUTRA. It is the shortest of all the great Sutras and on that account was memorised by all Buddhist monks and recited as part of the daily ritual, often many times a day. It is no wonder that its teaching of "emptiness" entered into the warp and woof of their thinking.