There are many ceremonies connected to the accession of a new Tennō, and last week’s Daijōsai is the most important Shinto ritual among them. The whole series is concluded with a performance of kagura, sacred music and dance, before the Kashikodokoro, where Amaterasu Ōmikami is enshrined within the Imperial palace. This time, the kagura will be offered in December, over the course of about six hours, starting around sunset. Jinja Shinpō carried a couple of articles about this on the 7th and 14th of October.
Fifteen songs are performed in the ceremony, divided into three groups of five: five to welcome the kami, five to entertain the kami, and five to see the kami off again. The tradition goes back over a thousand years, and it has slowly shifted in form. One part of that is particularly interesting.
The first song of the final section was originally entitled “Hirumë”, written with the kanji for “Eye of Day”, and derived from another name for Amaterasu Ōmikami, Ōhirumë-no-Muchi. It particularly emphasises the connection between the Tennō and Amaterasu Ōmikami, and for centuries it was performed by a member of the Ayanokōji noble family. From the seventeenth century, however, it came to be referred to as “Hikyoku”, which means “Secret Song”.
This is because of its mode of performance: this song is performed silently. There are five performers: two singers, a Japanese koto (“wagon”), a kagura fuë (a flute) and a hichiriki (a double reed wind instrument). The introduction involves all the performers, but the main song is only for the singers and the koto.
The performers properly perform the song. They actually touch the strings, blow into the flute and hichiriki, and breathe in and out appropriately while shaping their mouths into the words. However, they make sure that, while doing this, they make no sound at all. (Having some experience of singing, this sounds really hard to do.)
The author of the Jinja Shinpō articles is a researcher in traditional music, and she reports that other people in her field know of no other examples of this sort of practice. I am aware of no other examples in Shinto practice, either, although I think the Hikyoku is now also performed at Jingū after the Shikinen Sengū, the Grand Renewal. (I believe that this is a post-Meiji practice, but I am not absolutely sure; most of the kagura now performed at Jingū is post-Meiji, however.)
This sort of isolated phenomenon is called a “hapax”, and the word is normally used for a word that appears only once in a particular body of a language — sometimes only once in everything that survives of the language. It is, unsurprisingly, often hard to work out exactly what such words mean. The same is true here. I have no idea what the particular significance of this mode of performance may be. The silence keeps its secret.