How does Shugendō differ from other schools of Buddhist Practice?
There are many ways to approach this question. For example, broadly speaking Shugendo combines a universal doctrine (Buddhism) with a localised one (Practices centered on Jingi/Kami). Added to this are unique interpretations, pre-Buddhist/folk influences and practices derived from other schools of thought like Taoism (Onmyodo).
A fundamental aspect of Buddhist practice involves developing an understanding of fundamental non-production (anutpada; 本不生, honpushō), emptiness (sunyata;空, kū) and dependent-origination (pratītyasamutpāda; 縁起, engi).
These concepts refer to the fact that all phenomena arise through causes and conditions, and that nothing - including the self - has its own unchanging nature. All the schools of Buddhism employ various methods (方便; upāya/skillful means) to achieve this understanding, and use it as the basis to approach questions of grasping, aversion and ignorance, and to widen the scope for compassion, wisdom, clear perception and concentration (samadhi). Generalising, Zen Buddhism for example focuses on Zazen (坐禅; seated meditation) and the Pureland school focuses on Nenbutsu (念仏; devotional recitation practice on the Buddha Amida).
What then are the methods characteristic of the Shugen sects?
Shugen is not a school where teachings and practices are experienced passively; all true shugen schools require time, energy and discipline on the part of the practitioner and the deep union of theory and practice.
Shugendō's defining method is the use of periodic retreats and disciplined ascetic practice (修行; shugyō) in mountains and valleys. In Shugendō the sacred topography of the natural world becomes the site of practice (行場), where practitioners confront these questions and pursue an experiential understanding of the doctrine. Shugendō is an embodied tradition which needs to be learned and scrutinized by means of the body.
As a sect which due to historical reasons is closely linked to the Esoteric-Buddhism of the Shingon and Tendai schools, initiation, empowerment, ritual-practice and the direct teacher-disciple relationship are considered paramount. Esoteric-Buddhism - an extension of Mahayana - is characterised by yoga (本尊瑜伽); the creative union of the practitioner's body, speech and mind.
To flesh this out a little further, the following page will introduce readers through short articles by renowned figures from the various Shugendō sects.
Articles: What is Shugendo?
Kumano Ten Worlds Mandala