旧妙音山長光寺伝来盲僧琵琶「春日野」について

伝・景清ゆかりの琵琶

抄録

The ‘Kasugano’-biwa and its related documents have prompted this research. The ‘Kasugano’-biwa is a biwa which has been handed down to the Chokoji temple, the old-Mosojiin, in Miyazaki-shi as one closely connected with Taira Kagekiyo.
This biwa, which looks like a small-sized Gaku-biwa, can be considered a Moso-biwa because it has six frets. These frets are, however, not as tall or large as those of the presentday Moso-biwa, but small like those of the Gaku-biwa. The present-day Moso-biwa has a long shishikubi part and a small haraita part so that all the frets can be attached to the shishikubi part. The ‘Kasugano’-biwa, on the other hand, like a Gaku-biwa, has a small shishikubi part where only four frets can be attached. The other two frets are attached to the haraita part, which may suggest that they were added later.
It may also suggest that as the Heike-biwa in the Edo period was formed by adding a fifth fret to the Gaku-biwa, the ‘Kasugano’-biwa must have been formed by adding a fifth and sixth fret to the Gaku-biwa. This hypothesis can be proved true by its musical intervals. An experiment shows that the musical intervals from the first to the fourth frets are the same as those of the Gaku-biwa, while they are different from those of the present-day Moso-biwa. This means that the arrangement of musical intervals of this biwa followed that of the Gaku-biwa, but there was an addition of two musical intervals later.
While this biwa shares many points with the Gaku-biwa including a bachi-gawa, the form of the fukuju, the tsugenkou of the fukuju hemmed with suiteki forms, the form of the hangetsu, the engraved enzan on the backside and others, it also has many points common to the present-day Moso-biwa and Satsuma-biwa, such as a shichu behind the fukuju, a hangetsu hemmed with zogan, the form of the bachi, and the urushi paint covering the whole instrument.
Therefore, the ‘Kasugano’-biwa was probably formed following the Gaku-biwa tradition during the period of transition from the Gaku-biwa to the other type of biwa. This biwa can also be considered in the middle of the transition from the Gaku-biwa to the present-day Moso-biwa (with six frets). The transition appears to have happened in the following way.At first, the Gaku-biwa and then the small-sized Gaku-biwa were used as the Moso-biwa. After that, the form of the small-sized Gaku-biwa was changed into the present form with six frets by adding two frets on the haraita. Finally the shishikubi parts were lengthened and the haraita parts were made smaller.
A Naito-family (former Lord of the Nobeoka clan) document, which includes pictorial documents, suggests that the ‘Kasugano’-biwa was produced before or during Edo period. No further information is available at this time about the year it was made because we have no other Moso-biwa with the precise year of its production. In addition, as there is no historical evidence of the legend of Kagekiyo's visit to Hyuga, it is not certain that this biwa was cherished by Kagekiyo. It is not possible to maintain that it was produced while he was alive, namely at the beginning of the Kamakura period.