The Long Sūtra
The history of the longer version of The Heart Sūtra presents us with an equally complex picture of textual transmission. Notably, there are at least two distinct longer versions of The Heart Sūtra. Both longer versions add to the short sūtra by presenting a more extensive, traditional introduction (beginning with the statement “Thus did I hear at one time”) and a conventional concluding section as we generally know them from the Mahāyāna sūtras. As a result, the longer versions appear much more like a typical sūtra than does the short version.
The earliest version of the long sūtra, traditionally dated to 738 ᴄᴇ, is a text that only exists in Chinese (Taishō 252). While the text presents itself as a translation from Sanskrit, it is most likely an early attempt to present the short sūtra in a traditional literary format by adding an introduction and a concluding section, which appear to have been composed directly in Chinese. This version does not seem to have gained much popularity, as its unique introduction was never replicated or copied in other sources.19
The four remaining Chinese versions of the long sūtra (Taishō 253, 254, 255, and 257) are all translations that were produced either from Sanskrit or Tibetan manuscripts.20 Although they each feature certain idiosyncratic elements, all of them clearly belong to the same family in text-historical terms. Unfortunately, there are no surviving Sanskrit manuscripts from the period when these four translations were produced, from the late eighth to the early eleventh century.21 The earliest Sanskrit witnesses we have of the longer version of The Heart Sūtra are Nepalese manuscripts that were produced several centuries later.
Just as with the Sanskrit translation of the short sūtra, we also do not know the circumstances in which the Sanskrit text of the longer version first appeared. It must have taken place, however, prior to 788 ᴄᴇ, when the first Chinese translation from Sanskrit was produced. At around the same time, the two Tibetan translations, which were subsequently included in the Kangyur (see more below), must also have been produced. We can say that with some confidence, since the translation is recorded in the Denkarma catalog of completed translations, which is dated to 812.22
In the Tengyur collections seven commentaries on the long sūtra by Indian scholars and one by a Chinese scholar are included in Tibetan translation. Some of these commentaries were composed by such well-known names in Tibetan history as Kamalaśīla (740–95), Vimalamitra (eighth/ninth c.), and Atīśa (982–1054).23 The authors of these commentaries were all active from the eighth to the eleventh century and most of them are known to have visited Tibet. Interestingly, the different commentators view The Heart Sūtra through very diverse hermeneutical lenses and interpret it variously through the systems of sūtra, tantra, and even ritual practice (sādhana). This great variety of interpretations, combined with the fact that there is no mention of The Heart Sūtra in any other source linked to India, makes it seem likely that the commentaries were all composed in Tibet during the sojourns of these Indian masters there.24
It therefore appears that the history of the long sūtra can be told largely as a Sino-Tibetan exchange of ideas and manuscripts, which unfolded during the eighth to the eleventh century. In this regard, there are strong indications that the Dunhuang region was an important center for the exchange of such ideas and manuscripts. Among the scriptural treasures discovered in the Dunhuang caves in the early twentieth century, all of which must date prior to the turn of the eleventh century when the caves at Dunhuang were sealed off, there are numerous manuscripts of The Heart Sūtra in both Chinese and Tibetan. In addition to the shorter versions mentioned above, there are a number of longer versions, and apparently even a few “hybrid” manuscripts that are neither of the standard short or long sūtras.25 Like the Chinese and Sanskrit versions, these Tibetan Dunhuang manuscripts provide a variety of readings, but so far no comparative analyses of these texts, or critical editions of the manuscripts, have been published.