Stephen --
I'll let you in on a trade secret.
http://scholar.google.com/schhp?hl=en
The search <yamabushi tengu> done at a library with access to scholarly journals will give you weeks of reading. Even at home, one gets enough to keep one amused for quite awhile.
<yamabushi "martial arts"> turns up the usual suspects. Moving right along.
<yambushi bushi> turns up some better stuff. For instance, http://journals.cambridge.org/action...ne&aid=6966996
Looks like a lot of the good stuff is (unsurprisingly) in German. The Germans used to have a special relationship with Japan, and their universities often have Asian studies collections that are better than most North American university collections.
And, a heresy. (I am notorious for these.) For popular interpretations of the topic, take a look at theater (to include puppet theater), dance, and literature. For instance: http://enlight.lib.ntu.edu.tw/FULLTE...x012374340.pdf and http://faculty.humanities.uci.edu/sb...azell_3-43.pdf
This one looks relevant, too:
Shugendō: Pilgrimage and Ritual in a Japanese Folk Religion
Andrea K. Gill Follow
Abstract
The religion of Shugendō has no shrines and it has no temples. It only has the liminality of the mountains; a space that is viewed in Japan as being ground that only gods, demons, and ghosts may set foot on. But the Yamabushi are not human, gods, or even demons. Instead they are believed to be living Buddhas, rare people that, through practice in the secluded mountains, have become privy to sacred knowledge that has awakened them to their internal Buddha nature, to borrow the words of Kukai, “in this very lifetime”. One of the defining features of Shugendō is the relationship that is formed between man, gods, and nature in the context of the sacred mountain (Grapard, 1994). Another feature found strongly in Shugendō is the role that the Yamabushi play in the communities surrounding their sacred mountains.
Recommended Citation
Gill, Andrea K. (2012) "Shugendō: Pilgrimage and Ritual in a Japanese Folk Religion," Pursuit - The Journal of Undergraduate Research at the University of Tennessee: Vol. 3: Iss. 2, Article 4.
Available at: http://trace.tennessee.edu/pursuit/vol3/iss2/4