"Not turning away from the experience of suffering, practitioners will naturally arrive at the fruits of realisation."
— Attributed to En no Gyoja.
Early Shugen doctrinal texts consist of collections of ritual-memoranda outlining longstanding reserved oral traditions based on direct transmission between master and disciple. These collections reveal Shugen's fundamental approach as well as being ritual (practice) texts. Modern ritual-memoranda and practice-texts, too, consist of brief instructions devoid of context. That is, understanding them requires direct-transmission through the student-teacher relationship. This also means that certain teachings are reserved in the sense that they require the practitioner to demonstrate a basic level of commitment and responsibility.
Much of what constituted Shugendo as a living tradition was greatly impacted by the Meiji Period's persecutions and dismantling. This is the driving force behind the joint efforts towards revival of Shugen tradition by the legitimate Shugen sects, characterised by Haguro (Kotakuji-Shozenin) and Koshikidake-Kannonji as 'old-school/old-style Shugen' (kōryū shūgen).
So what forms the doctrinal basis of Shugen as a living tradition practiced today?
Shugen literature assumes a deep appreciation of Mahāyāna and Mantrayāna (Esoteric) thought, as well as familiarity with 'traces and grounds' discourse, 'original-wakefulness' discourse, texts concerning astrology and divination, yin-yang discourse, folk-shinto/Shinto mythology and so on.
Within Shugen texts themselves, we find references made to Avataṃsaka, Prajñāpāramitā, Saddharma-puṇḍarīka, Ekayāna and Yogācāra thought, as well as their corresponding sutras. Adding an advanced layer to the foundation of Mahāyāna are esoteric sutras and teachings which form the basis of ritual (sādhanā) practice (as 'experiential' sutras). From this, we can see that despite Shugen's characterisation as a broad-brush, lay-oriented school transmitted 'outside of the scriptures', this does not mean that its approach to practice and insights does not require a deep understanding of theory, without which it becomes easy to fall into confusion or incorrect views.
While teachings form the conceptual runway, Shugen doctrine ultimately takes form through (guided) practice, both through mountain-entry asceticism and through its unique ritual-sādhanā. Often characterised as learned through the body, just as the kāṣāya in Buddhism signifies the renunciation of the practitioner, the implements and vestments of the practitioner of Shugen all serve as mnemonic devices which simultaneously guide doctrinal-osmosis and reflect the cultivation and inner-realisation of the practitioner.
As mentioned, Shugendo as a living tradition, clearly defines itself as a Dharma teaching and practice-path transmitted 'outside of the scriptures', directly between master and disciple. For this reason, it is difficult to talk about a single 'Shugen doctrine' because (despite the Academic gaze) these teachings (skillful means) were (are) always contextual and gradually expanded upon between master and disciple based on the disposition, capacity and inclination of the student. This is evident within memoranda collections themselves which are often separated based on 'superficial', 'shallow', 'deep' and 'profound' interpretations. Sometimes this relational approach involves adding gradual layers of depth to previous teachings, but more often than not it involves a complete re-contextualisation, similar to the ways in which Mahāyāna doctrine reframes and recontextualises the Hinayāna.
Shugen doctrine ultimately takes form through its interpretations and re-contextualisations of Mahāyāna doctrine and practice. From this, I hope it is clear that to appreciate and understand Shugen, as well as its characteristic skilful-means of ritual-sādhanā and mountain-entry asceticism, requires a strong grounding in Buddhadharma and Mahāyāna thought in particular. I often receive requests asking for starting points on engaging with Shugen. My advice is always to begin with a broad grounding in the sutras and commentaries of the Mahāyāna. With this in mind, what is discovered depends largely on the quality of approach, and so texts frequently warn that without bodhicitta (right aspiration) all practice will amount to 'nothing but the barking of a fox'.
What follows is Part 1 of my translation of the 'Basic Foundations in Buddhism' lectures as delivered through Kinpusen-ji temple's gyō-in (practice-hall) by Reverend Professor Masahiro Asada (as supervised by Rev. Riten Tanaka). These were first published in Kinpusen-jihō, a bulletin of Kinpusen-ji temple, between 1986 and 1991. As mentioned, the ideal in Mahāyāna is a teaching of skillful means (upāya). That is, generally speaking, teachings should be prescribed only according to the specific context and inclinations of the person asking. Nonetheless, I hope that readers find this series useful.