Koto scales and tunings
Masateru Andô · The Journal of the Acoustical Society of America · 1988
The koto, an instrument consisting of 13 strings stretched over a long sounding board, is tuned by a set of movable bridges, one for each string. The koto's musical range normally extends from A1 to A7. Within this range, two and a half octaves are most commonly utilized. Excluding modern pieces, most koto pieces are constructed from a five-tone scale. Generally classified, there are two types of scales that can begin on any tone; a minor-sounding scale (mi-fa-la-si-do-mi), and a major sounding scale (re-mi-sol-la-si-re). The most common tuning is known as Hira-jôshi, which begins on the fifth string of the koto and follows the minor-sounding scale noted above. Tuning on the koto is accomplished by first setting string No. 1 to the desired pitch. Then the fifths, fourths, octaves, firsts, and minor seconds are tuned, creating a scale close to the Pythagorean scale. Like piano tuning, inharmonicity is observed. Several of the traditional tunings for koto music have the same scale as the minor-sounding Hira-jôshi except that they begin on a different string; No. 6, 7, 8, or 9, rather than string No. 5. Likewise, the major-sounding scales can begin on any of the same five strings.