Physical Properties of the Reed (Phragmites australis) Used for the Vibrating Plate of the Japanese Oboe (Hichiriki) I Density variation in the culm and compressive strength in the transverse direction

摘要

Hichiriki is a traditional Japanese oboe used for Japanese ancient court music (Gagaku). The vibrating plate (Rozetsu) of the hichiriki is made from a reed (Phragmites australis), and the best reed is believed to be harvested in the Udono area along the Yodogawa river. In this study, we observed the anatomical structure of reeds selected by experts, and measured their density and transverse compressive strength to clarify the basic requirements for quality instruments. Within an internode, the upper part was always thinner and denser than the lower part, depending on the thickness of the low-density parenchyma layer beneath the cortex. Selected reed was slightly thicker and denser than unselected reed, but those differences were not significant. On the other hand, the transverse compressive strength of selected reed was significantly greater than that of unselected reed, and the upper part showed the highest strength. It is considered that sufficient transverse strength is required while the thinner, i.e. deformable upper part is preferred, because an end of the reed culm is compressed to form the closed end of the double-reed. With respect to shape, density and compressive strength, the Mukaijima area along the Uji river is a potential field to harvest reeds for hichiriki.