The Horagai (法螺貝) is a wind instrument used in Japan, based on the conch shell. The conch shell, which is blown in the same way as a trumpet, served many purposes throughout the history of Japan and was called jinkai (陣貝), horagai (法螺貝), and a series of other distinct names in Japanese depending on its function.
Religious and Military Use of Horagai
Perhaps the most well-known use of this instrument is by Buddhist monks for religious purposes. Its use dates back at least a thousand years and is still used in some rituals such as the Omizutori, which is part of the Shuni-e rites at the Tōdai temple in Nara. Unlike the conch shells used in other cultures that produce only a single tone, the Japanese horagai can produce between 3 and 4 different notes.
The horagai is also especially associated with the yamabushi, who used it to signal their presence or movements among themselves in the mountains or as accompaniment to the sutras.
Horagai in Warfare
During war, a conch shell called jinkai or war conch was used as a signaling trumpet. A large conch with a bronze (or wood) mouthpiece was used, which emitted notes depending on the order that the commander wanted to communicate to the troops: attack, retreat, change strategy, etc. The trumpeter was called kai yaku (貝役). The jinkai had a use similar to that of taiko drums and bells in signaling troop formation, setting the marching rhythm, providing heroic accompaniment to encourage troops, or confusing the enemy by making them believe that the troops were more numerous than they actually were. Many daimyō used to hire yamabushi to serve as kai yaku due to their experience with the instrument.