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般若心經祕鍵

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Text ID
KR6c0199
Date
818–818
Dynasty
日本

Bānruò xīnjīng mìjiàn 般若心經祕鍵

The Secret Key to the Heart Sūtra by 空海 (撰)

About the work

空海 Kūkai’s principal commentary on the Prajñāpāramitā-hṛdaya (KR6c0128, Xuán-zàng’s Heart Sūtra). One-juan, composed in 818 CE under the Esoteric-ordination signature Henjō-Kongō 遍照金剛, with a colophon (in the form of shàng-biǎo 上表, “memorial-presented”) attributing the work explicitly to Kūkai. Among the most famous and influential of all Kūkai’s writings — one of the principal Japanese Esoteric scriptural commentaries of the Heian period, and a foundational document of the Shingon school’s reading of Prajñāpāramitā literature. It establishes the Esoteric maṇḍala-deity reading of the Heart Sūtra that has been the standard Shingon interpretation ever since. Preserved in Taishō Vol. 57, No. 2203A.

The compilation in the Taishō under T2203 splits into two parts: T2203A is Kūkai’s Hiken proper, and T2203B is 覺鑁 Kakuban’s sub-commentary on it (the Hiken ryakuchū 祕鍵略註, KR6c0200). The companion late-Heian sub-commentary by 濟暹 Saisen is preserved separately as T2204 (KR6c0201).

Abstract

Date and occasion. The colophon supplies an exceptionally specific dating: yúshí Kōnin jiǔnián chūn, tiānxià dàyì 于時弘仁九年春，天下大疫 — “In the spring of Kōnin 9 (= 818 CE), there was a great plague over the realm.” In response to the epidemic Emperor 嵯峨 Saga personally copied out the Heart Sūtra in gold ink on indigo paper, and Kūkai composed the present Hiken as a doctrinal-ritual commentary on the imperially-copied text: yú fàn jiǎngdú zhī zhuàn, zhuì jīngzhǐ zhī zōng (“I, [Kūkai], at the formal lecture-and-recitation, composed this exposition of the sūtra’s central import”). The colophon further reports that before the closing-prayer-words were even pronounced, the dying-and-revived people [filled] the roads, night turned to day, and the radiance shone forth — attributing the cessation of the plague to the merit of the imperial sūtra-copying together with Kūkai’s Hiken. This dating is secure and uniquely precise among Kūkai’s commentarial works; both notBefore and notAfter are 818.

Doctrinal architecture. The work opens with a six-line shī praising the four-fold dynamic of Mañjuśrī’s sword cutting the proliferations, the Mother of Awakening, mantra as seed-syllable, and dhāraṇī as the canonical store. The doctrinal frame is signature Kūkai-Shingon: the Heart Sūtra, on its surface a second-period unfinished Prajñāpāramitā teaching bō-ruò dì-èr wèi-liǎo zhī jiào 船若第二未了之教, in fact contains the entire Esoteric Vajra-summit doctrine — yī-zì hán wǔ-shèng zhī yì, yī-niàn shuō sān-zàng zhī fǎ 一字含五乘之義，一念説三藏之法 (“a single letter contains the meaning of the five vehicles; a single thought speaks the three treasuries”). The methodological maxim is yī-zì hán qiān-lǐ 一字含千理 (“a single syllable holds a thousand principles”).

The five-fold maṇḍala-reading. The core contribution is Kūkai’s segmentation of the Heart Sūtra into five sections, each identified with a particular Esoteric maṇḍala deity representing a distinct yāna / vehicle:

  1. Rén-fǎ zǒng-tōng fēn 人法總通分 (“person-and-Dharma general-comprehensive section”) — opening through 度一切苦厄; the Avalokiteśvara samādhi of guān-zì-zài (the Heart Sūtra’s announced bodhisattva).
  2. Fēn-bié zhū-shèng fēn 分別諸乘分 (“differentiating-the-vehicles section”) — from 色不異空 to 無所得故; five-vehicle exposition with sub-deities — jiàn 建 (Samantabhadra, 建立如來: round-cause perfect-fusion); jué 絶 (Mañjuśrī, 無戲論如來: eight-no-cutting); xiàng 相 (Mahā-mantra-bodhisattva: Yogācāra-Vijñaptimātratā); èr 二 (the two lesser vehicles, yuán-jué + shēng-wén); yī 一 (Avalokiteśvara as one-vehicle).
  3. Xíngrén déyì fēn 行人得益分 (“practitioner-attainment section”) — from 菩提薩埵 to 三藐三菩提; benefits attained.
  4. Zǒng-guī chí-míng fēn 總歸持明分 (“comprehensive-dhāraṇī section”) — from 故知般若 to 眞實不虚; the four-fold mantra-form designation.
  5. Mì-zàng zhēn-yán fēn 祕藏眞言分 (“Esoteric mantra section”) — gate gate pāragate pārasaṃgate bodhi svāhā; the five-vehicle culmination-mantra.

Each section is presented in prose plus a four-line summary jié (頌). The architectural move is to map the discursive five-vehicle Buddhist doctrinal taxonomy (śrāvaka, pratyekabuddha, Yogācāra, Mādhyamika, Esoteric) onto five segments of the Heart Sūtra, then identify each segment with the maṇḍala-deity whose Esoteric samādhi corresponds to that yāna. The closing mantra is read as the culminating Esoteric statement that unifies all five vehicles.

Polemical defense. A series of dialogical wèn (問) sections at the close defends the project against an obvious traditional objection: prior translators and commentators have, with one accord, declined to gloss the dhāraṇī as the proper response to its esoteric character — so why does Kūkai violate this rule? Kūkai’s answer is the xiǎn-mì doctrine: the Tathāgata teaches in two ways, xiǎn (for the apparent-faculty audience: through many names and phrases) and mì (for the esoteric-faculty audience: through dhāraṇī-syllable). The Tathāgata himself glosses the syllables 字字 with various meanings in the Vajra-summit corpus — 龍樹 Nāgārjuna, 善無畏 Śubhakarasiṃha, 不空 Amoghavajra have all written such commentaries. Kūkai is therefore writing for the Esoteric-faculty audience; the prior commentators’ silence was suited to their apparent-faculty audience. Neither approach contradicts the Buddha’s intent.

Historical importance. The work is the single most cited and commentated of Kūkai’s writings. It established the canonical Shingon reading of the Heart Sūtra and made the sūtra the principal Esoteric prajñā text of daily Shingon liturgy alongside the Rishukyō.

Translations and research

  • Hakeda Yoshito, Kūkai: Major Works (Columbia, 1972) — full English translation under the title “Secret Key to the Heart Sūtra,” with introduction. The principal English translation; widely cited.
  • Thomas Eijō Dreitlein, “An Annotated Translation of Kūkai’s Secret Key to the Heart Sutra,” 高野山大学密教文化研究所紀要 24 (2011): 1–48 — modern revised English translation with extensive annotation.
  • Ryūichi Abé, The Weaving of Mantra (Columbia, 1999) — extensive treatment of the Hiken’s significance for the construction of Esoteric Buddhist discourse.
  • Donald S. Lopez, Jr., Elaborations on Emptiness: Uses of the Heart Sūtra (Princeton, 1996) — situates the Hiken within the broader Heart-Sūtra commentarial tradition.
  • Substantial Japanese-language commentarial literature: Matsunaga Yūkei 松長有慶, Yamasaki Taikō 山崎泰廣, and the modern Mount Kōya scholastic tradition.

Other points of interest

The historical-political situation of the work’s composition — an emperor (嵯峨 Saga) personally copying out the Heart Sūtra in gold, with Kūkai composing the Hiken as the lecture-text at the imperial sūtra-recitation ritual — is one of the most consequential moments in the institutional history of Japanese Buddhism. It established the Heian-court pattern in which scriptural copying by the emperor + Esoteric ritual exegesis by Kūkai functions as state apotropaic ritual against plague and disaster, a pattern that would shape imperial Buddhist patronage for centuries. The Hiken itself is consequently not only a doctrinal commentary but also a political-ritual document: the proof-text for the symbolic alliance between the 嵯峨 Saga court and the early Shingon school.

The textual situation is unusual: the Hiken is presented in the standard shàng-biǎo (上表 “memorial-presented”) form addressed to the emperor, with the author’s self-designation rù-Táng shā-mén Kōng-hǎi 入唐沙門空海 (“the Cháng-ān-trained śramaṇa Kūkai”) rather than the more usual Esoteric henjō-kongō 遍照金剛. The biǎo form positions the text simultaneously as scholastic commentary and as imperial-court ritual document.

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