佛教藝術裏的肉髻僧人形象及其興衰的成因

Images of Monk with Uṣṇīṣa in Buddhist Art and the Reasons of the Rise and Fall of This Iconography

釋迦牟尼佛生有三十二大人相，肉髻是其中之一。在佛教藝術裡，肉髻已成為佛像的專屬標誌。但是曾經有過僧人的圖像也明顯地帶有肉髻，主要出現在以龜茲為中心的絲綢之路北路，吐魯番地區也有不少，最早可以追溯到犍陀羅等地的一些零星石刻和阿旃陀石窟。有肉髻的僧人形象是佛教藝術裡一種非常獨特的圖像，對這一圖像，雖有Monika Zin 對以印度為主的圖像進行了識別，但至今仍鮮為人知，沒有引起中國學者的關注。本文以龜茲和吐魯番地區為重心，分析各地肉髻僧人形象的特點，辨析他們的身份；並在佛教理論中，探索這些人物為什麼會有肉髻，以及這一圖像興衰的原因。一切有部是龜茲的主導教派，在吐魯番、犍陀羅和阿旃陀這些出現過肉髻僧人圖像的地方也有活動。本文揭示一切有部文獻對大人相的特殊關注，並指出這種關注與菩薩乘思想之間的關係。肉髻僧人的圖像在今天的東南亞的小乘佛教和東亞的大乘佛教藝術中都沒有。對肉髻僧人圖像的研究，可以增進我們對佛教史上一些重要概念及問題的認識，如對佛身及相好本質的理解的變遷史，以及晚期小乘部派中菩薩乘的興起等等。

Śākyamuni is supposed to have been born with the mahāpuruṣa lakṣaṇas (characteristics of the Great Person). The uṣṇīṣa, “the protrusion on top of the head,” is one of his characteristics. In standard Buddhist iconography, the uṣṇīṣa is an attribute almost exclusive to the Buddha image. However, some monk images in very limited areas, mostly caves from the Kizil and Bezeklik regions in Central Asia and Ajaṇṭā caves in India, are clearly shown with this cranial protuberance. The purpose of this paper is to examine this unusual iconography and study the signifi cance of endowing the uṣṇīṣa on the non-Buddha fi gures in Buddhist theory and practice. Attempt will be made in searching the possible connection among the areas where this iconography appeared, and how this may be related to Sarvāstivāda, a Hīnayāna school which is believed to have dominated Kizil and also have existed at the sites of Bezeklik and Ajaṇṭā. Since the Kizil caves yield the most intensive depiction of such images and the images at Bezeklik bear inscriptions that are crucial for interpreting the meaning of the iconography, I will focus on the images from these two regions, which have not been extensively studied. I propose that the interest to gain the Buddha's mahāpuruṣa lakṣaṇas is linked to the movement of Bodhisattvayāna, which can be tested in the buddhanusmṛti practice in a Sarvāstivādin manuscript excavated from the Kizil cave site, i.e., to call vision of the Buddha by visualizing the Buddha's body and eventually envisioning oneself bearing the mahāpuruṣa lakṣaṇas of the Buddha. In reviewing the history of the concept of the uṣṇīṣa, special attention will be given to the yanic nature of the different understandings of the mahāpuruṣa lakṣaṇas in order to explain why the image of the monk bearing the uṣṇīṣa is a late Hīnayāna iconography. It was absent in early Buddhist art and becomes largely absent in Mahāyāna Buddhist art in East Asia.