The December 19th/26th issue of Jinja Shinpō had an article introducing the following YouTube video.
This was made by the Northern Tama Young Priests’ Association with Suzuë, a singer who is also a priest. (Northern Tama is the rural area of mainland Tokyo.) In this video, Suzuë sings the “Hifumi-no-Haraëkotoba” several times.
The “Hifumi-no-Haraëkotoba” consists of all 47 unvoiced Japanese syllables, once each. The first ten are the numbers one to ten in their Japanese readings (or, at least, the first syllables of them), but they could be read in other ways. The notes on the video attribute the prayer to the Sendaikujihongi, a (probably) ninth century book that gives the mythic history of Japan, with some content that is not in the Kojiki or Nihonshoki, and a lot that is. However, I’ve checked a few books, and it looks as though it is actually from the Sendaikujihongidaiseikyō, which is a different work, and probably from the seventeenth century. (The first ten syllables are referenced in the Sendaikujihongi as a set, however.)
The meaning of the prayer is obscure, and it has been interpreted in many ways over the years. It is rather more esoteric than most things found in mainstream Shinto these days, but still clearly part of the tradition. I thought people might enjoy the video.