解深密經（Sandhinirmocana-Sutra）自劉宋求那跋陀羅剏翻，中經元魏菩提留支、陳真諦兩家，至唐玄奘法師，凡有四譯。其中宋、陳兩譯僅節取全經少分。魏、唐二本為全譯而品目開合略別。此經境、行、果三，賅攝無餘。陀那深細，明身心之一如；如來成事，顯佛地之業用；判三時之淺深，暢一乘之宗極；闡止觀于瑜伽，辨了義于三性；理事悉備，要言不煩；誠大乘之綱領，法相之鈐鍵也。昔玄奘法師于中印度那爛陀寺聽戒賢法師為講「瑜伽論」三遍，而此經除序品外，全文收入「瑜伽論（卷七十五～七十八）」中，故奘師于此經可云盡得戒賢之心傳。及其周游西宇，學滿還唐，所出經論，隨翻隨講，弟子錄記，多存口義。奘門多賢，測、基稱首。圓測法師（六一三～六九六）者，以新羅之王孫，為釋迦之法嗣；三齡入道，餐勝義于孩提；十五受業，揚德輝于邦域。乃以志切弘通，振錫西來，游方參學，聲聞日遠。貞觀之末，慈恩東返，長安一遇，宛若舊知。由是瑜伽、唯識，瀉瓶無隱，終始譯業，倚畀良殷。測師奉侍無違，咨承無厭，竺賢深義，所得獨多。所作「解深密經疏」十卷（金陵刻經處本合有四十卷），廣徵教典，備存師說，持論精審，為世寶重。時令因、玄范、憬興、元曉各家，并有疏記，遭會昌法難，散佚無存。獨測師此疏，以東邦學僧賚持還國，累業傳習，賴以不墜。清末石𥓏楊仁山居士曾自扶桑（日本）取回刊印，流布海內，慧炬掩千祀而復明，絕學涉萬濤而還續，法相重興，功德不朽，惜原本以祀綿遠，致有殘缺，其中九卷（金陵刻經處刻本當第二十七卷）失品題之釋，十卷（金陵刻經處刻本當第三十五至第四十卷）成無字之章，德海汪洋，悵失舟楫。欲渡無航，學者憾焉。然西藏（丹珠藏）中譯存此疏全文。譯者法成法師，晚唐西蕃大德也。法師出生廓（Hgos）氏望族，為西藏佛教前宏期著名譯師，精嫻梵、藏、漢土文字，約于唐大和七年（八三三）來游沙州，爾後往返甘、沙兩地，譯經說法，垂三十年（約八三三～約八五九）。由敦煌遺書中尚可考見，其由漢譯藏者有十餘部，由藏譯漢者數部，經論講疏若干部，皆為三藏要籍。所有譯文，今以傳本對勘，見其譯義精當，屬辭雅訓，誠譯事之上乘也。至其講疏（瑜伽）大論，更能校漢、藏兩譯之異同，探彌勒、無著之深意；顯微闡幽，開比較研究之徑蹊；正言斷辭，導科學治經之先路，稽之往史，洵屬難能。測疏得其譯存，全文得以不泯，謂非千古幸事耶？

The *Sandhinirmocana Sūtra* (Sūtra of the Profound Revelation) was first translated into Chinese by Guṇabhadra during the Liu Song dynasty, followed by translations by Bodhiruci of the Northern Wei, and Paramārtha of the Chen dynasty. Finally, it was translated by the Tang dynasty Master Xuanzang, making a total of four translations. Of these, the Song and Chen versions are partial, covering only small portions of the full text. The Wei and Tang editions are complete, though their chapter divisions differ slightly. This sūtra comprehensively covers the three aspects of the Buddhist path: View (perspective), Practice, and Fruit (realization). It elucidates the deep and subtle nature of the *ālayavijñāna* (storehouse consciousness), revealing the unity of mind and body; it clarifies the Tathāgata's accomplishments, manifesting the activities and functions on the Buddha ground; it distinguishes the three turnings of the Dharma Wheel in terms of their profundity, and perfectly expresses the ultimate intent of the One Vehicle; it explains calming (*śamatha*) and insight (*vipaśyanā*) meditation within the framework of Yoga, and discerns the definitive meaning through the Three Natures (*trisvabhāva*). Principle and practice are fully covered, the essential teachings are presented without unnecessary complexity. It is truly the hallmark of Mahāyāna and the key to the Dharma-character school.

In the past, Master Xuanzang, at Nālandā Monastery in central India, listened as Master Śīlabhadra explained the *Yogācārabhūmi-śāstra* three times. Since this sūtra, apart from its introductory chapter, is contained in its entirety within the *Yogācārabhūmi-śāstra* (Chapter 75-78), Master Xuanzang can be said to have fully received Śīlabhadra’s essential transmission. After he traveled extensively throughout India, completed his studies, and returned to Tang China, he translated sūtras and treatises while simultaneously explaining them. His disciples recorded these oral commentaries, preserving many of his personal interpretations.

Master Xuanzang’s disciples were numerous and talented, with Woncheuk and Kuiji being the foremost. Master Woncheuk (613-696), a prince of the Silla kingdom and a Dharma heir of the Buddha, entered the monastic path at the age of three, partaking of the supreme meaning even in childhood. At fifteen he began his formal studies, spreading his virtuous fame throughout the land. With a fervent aspiration to propagate the Dharma, he traveled westward, studying and learning widely, his reputation growing ever brighter. In the final years of the Zhenguan reign, when Xuanzang returned east to Chang'an, their meeting there was like that of old friends. From then on, Xuanzang poured forth the teachings of the Yogācāra and Vijñaptimātratā without reservation, relying heavily on Woncheuk’s assistance throughout his translation career. Woncheuk served Xuanzang without deviation and sought his guidance without satiety, thus gaining a profound understanding of the Indian master’s deep meaning. His ten-fascicle *Commentary on the Sandhinirmocana Sūtra* (which, in the Jinling Scriptural Press edition, is combined into 40 fascicles), extensively cites scriptures and treatises, preserves the master’s oral teachings, and is known for its precise reasoning, treasured by the world.

At that time, various other scholars—Lingyin, Xuanfan, Jingxing, and Wonhyo—also composed commentaries and notes on this sūtra, but due to the Huichang persecution of Buddhism, these works were lost. Only Woncheuk’s commentary survived, preserved because it was taken back to his home country by a scholar-monk from the East (Japan), where it was studied and transmitted through successive generations, thus remaining safe from destruction. In the late Qing dynasty, the lay scholar Yang Renshan (of the Shiyin Studio) brought it back from Japan (Fusang) for printing and distribution throughout China. The lamp of wisdom, which had been darkened for a thousand years, was thus reignited; a lost teaching, having crossed ten thousand waves, was restored and continued. The Dharma-character school was revived, an achievement of everlasting merit. However, because the original text is old and incomplete, the commentary on one chapter (the equivalent of fascicle 27 in the Jinling Scriptural Press edition) is missing its explanatory title, and ten chapters (the equivalent of fascicles 35-40 in the Jinling Scriptural Press edition) are blank pages, leaving the vast ocean of virtue without a boat for crossing. Scholars lament this, unable to reach the other shore.

However, the complete text of this commentary is preserved in a translation found in the Tibetan *Tanjur* (*Dān zhū’ěr*). The translator, Dharma Master Facheng, was a great 9th-century Tibetan master of the late Tang period. A scion of the noble *'Gos* clan, he was a renowned translator of the Early Propagation period of Tibetan Buddhism. Proficient in Sanskrit, Tibetan, and Chinese, he came to the Shazhou region around 833 CE (the 7th year of the Taihe era). He then traveled between Ganzhou and Shazhou for nearly thirty years (c. 833-859), translating texts and expounding the Dharma. The Dunhuang manuscripts reveal that he translated over ten works from Chinese into Tibetan, several from Tibetan into Chinese, and numerous commentaries on sūtras and treatises, all crucial texts of the Buddhist canon. A comparison of these translations with extant texts shows his renderings to be precise in meaning and elegantly worded, truly a master of translation. Moreover, in his oral commentaries on the *Yogācārabhūmi-śāstra*, he compared the Chinese and Tibetan versions, exploring the deep intent of Maitreya and Asaṅga, revealing subtle and abstruse points, opening a path for comparative study. His precise language and reasoned arguments blazed a trail for a scientific approach to scriptural studies. In all of history, this is a rare and remarkable achievement. That Facheng’s translation allowed Woncheuk’s commentary to be preserved in its entirety is truly an extraordinary piece of fortune for all ages.

茲有觀空法師，幼稟道心，長懷卓志，仰奘師之景行，慕成公之高風，蜀道崎嶇，不懈探驪之愿；雪岭巍峨，終獲象罔之珠；住藏卅載，聞修并勤；言返首都，譯述不倦；「測疏」殘佚，每懷痛惜；誓譯藏本，用補缺文；黽勉二載，功業畢具，殺青甫就，徵序于余。余維「深密」法門，傳于彌勒，授于戒賢，譯于玄奘，述于圓測，寶藏于東瀛，譯存于西藏，上下千百年，廣員數萬里，合印、漢、藏、朝、日無數大德之力，展轉授受，始得幸存天壤。今者金甌復完，觀師之功居首，遠紹古德之殷勤，近慰時賢之渴望。合浦珠還，喜法寶之重歸；連城璧返，慶研幾之有據，豈僅佛教不思議之勝緣，抑亦竺、漢、藏、朝、日文化交流史之一勝事也。余故樂而為之序。雖然，猶有進者，漢本「測疏」傳世既久，展轉移錄，難免魯魚之訛。成公譯本距測師不過百餘年，去古未遠，所據原文，必更近真。若能對勘漢藏全疏異同，錄為校記，以餉學人，則功德更為圓滿矣，此一事也。又聞「丹珠藏」中尚有無著菩薩所作「解深密經釋」，文約義豐，為斯宗要典，譯而出之，與此疏相輔而行，則更如畫龍點睛矣，此又一事也。質之高賢，以為何如？是為序。

Now then, there is the Dharma Master Guan Kong. From childhood he was endowed with a heart for the Way, and as he grew, he nurtured lofty aspirations. He looked up to the noble example of Master Xuanzang and admired the high character of Master Cheng Guan. Though travel in Sichuan was treacherous, his determination to seek the pearl of wisdom never wavered. Though the snowy peaks were magnificent, he eventually obtained the elusive jewel of enlightenment. He resided in Tibet for thirty years, diligently combining study with practice. When he returned to the capital, he tirelessly engaged in translation work. The loss and fragmentary state of the *Ceshu* commentary grieved him deeply. He vowed to translate the Tibetan version to fill the gaps in the text. After two years of strenuous effort, the work was complete. As soon as it was finished, he asked me to write a preface for it.

I reflect that the teachings of the *Sandhinirmocana Sutra* were transmitted by Maitreya, bestowed upon Shīlabhadra, translated by Xuanzang, and commented upon by Woncheuk. Its treasures were preserved in Japan, and its translations were kept in Tibet. Spanning over a thousand years and stretching across tens of thousands of miles, the combined efforts of countless great masters from India, China, Tibet, Korea, and Japan allowed it to be passed down, ensuring its survival in this world. Now the golden bowl is whole again. Master Guan Kong’s contribution is foremost. He continues the earnest efforts of ancient sages while fulfilling the eager hopes of contemporary scholars. It is as if the pearl of Hepu has returned—we rejoice that the precious Dharma has been restored. It is as if the jade of Liancheng has come back—we celebrate that there is now a solid basis for study and research. This is not only a wondrous occasion for Buddhism, but also a remarkable event in the history of cultural exchange between India, China, Tibet, Korea, and Japan.

Thus, I am delighted to write this preface. However, there is still more to be done. The Chinese version of Woncheuk’s *Detailed Commentary* (*Ceshu*) has been passed down for a long time and, through repeated copying, inevitably contains textual errors. Master Cheng Guan’s translation was completed barely over a hundred years after Woncheuk’s time, so it is not far removed from the original. The source text he used must therefore be closer to the authentic version. If we could compare the Chinese and Tibetan versions of the full commentary, noting their similarities and differences, and compile these into a critical apparatus for the benefit of scholars, our merit would be even more complete. That is one task.

Furthermore, I have heard that the *Tengyur* contains a text called *Explanation of the Sandhinirmocana Sutra* by the Bodhisattva Asaṅga. Its words are concise yet rich in meaning and serve as a key text of this school. Translating it and making it available, so that it complements this commentary, would be like adding the finishing touch to a painting of a dragon by dotting its eye. That is another task.

I humbly ask the noble and wise ones what they think of this. This, then, is my preface.

Commentary on the Saṃdhinirmocana Sūtra ( (解深密經疏（補篇）)

Commentary on the Saṃdhinirmocana Sūtra ( (解深密經疏（補篇）)