Koto

Description

The koto is a thirteen-string zither, approximately 190 cm long and 25 cm wide (75 inches long and 10 inches wide).

Tuning

The koto sounds as written, and it is tuned to an A-430Hz. The strings are numbered from the lowest (first string - outer) to the highest (thirteenth string - the inner, closest to the musician).

Tuning is accomplished by changing the position of the movable bridges under the strings, which are plucked with plectra placed on the thumb, index, and middle fingers of the musician's right hand.

The plectra used for the perfromance of gagaku music are quite different from those used in zoku-sō (secular koto music, Yamada-ryū and Ikuta-ryū), which was developed after the 17th century. In gagaku, a plectrum is made of a relatively small bamboo piece, which is fixed onto a round bandmade of animal skin. The popular left hand technique used in zoku-sō music such as pressing or pulling a string to modify its pitch was used in the performance of gagaku music during the Heian period but since then that practice has been lost. Nowadays, the left hand simply rests on the instrument's table.

Figure 3 introduces the koto's seven traditional tunings. In Banshiki-chō and Hyō-jō, there are two tunings, one for ritsu tuning and the other for the ryo tuning. The former uses respectively A and D for the 6th and 11th strings, while the latter uses G# and C#.

Although the sound of the koto resonates more than the biwa's, three observations can be made about it:

• The plucking position of the right fingers must be as close as possible to the bridge to ensure maximum volume.
• There is a difference in the sound quality between the attack of the thumb and the other two fingers. The thumb attacks the string by upward motion while the two other fingers attack the string by downward motion, and because there is more strength in a downward attack, the two fingers create a stronger sound than the thumb's attack.

Figure 6 shows the spectra of a D4 played ff plucked with the middle finger (in blue) and the thumb (in red). The sound quality of a pitch attack by the middle finger is richer than when attacked by the thumb.

1. As seen under 'Traditional performance practices', most of the koto's melodic patterns involve the octave, not only because it falls well under the hand, but also because it provides maximum resonance.

Traditional performance practices

The koto has two types of patterns: metrical and non-metrical patterns.

Metrical patterns

Most metrical patterns are two-measures long. There are two basic patterns that fit this category: shizugaki and hayagaki (The examples are in the Ichikotsu-chō mode (D mixolydian))

a. Shizugaki starts its rhythmic activity on the 2nd beat of the first measure

b. Hayagaki starts its rhythmic activity on the 1st beat of the first measure

These patterns can be transposed to any of the pitches from the mode, but the fingerings and the string sequences remain the same. Because of the idiosyncratic tunings of this mode, such transpositions do not always generate the same intervallic sequences, as illustrated in Example 2 which demonstrates a transposition of Example 1.

There are various techniques to embellish and vary the basic sounding pattern of the koto, such as, among others: use of grace notes: kozume, sawaru, and ren.

• Grace-note: The pitch of the 2nd beat of the first measure of the shizugaki pattern is emphasized in three ways: First, this pitch is accentuated with a strong attack of the middle finger, and second, it is repeated one octave higher on the third beat. Finally, the last pitch, which is the highest one in the melodic pattern, is preceded by a grace-note that has the effect of accentuating it.

• Kozume: This is a special type of attack from the thumb attacking the string from underneath. The resulting sound is softer than the usual thumb's attack from above. When used with the shizugaki pattern it appears on the 1st beat of the 2nd measure. When used with the hayagaki pattern it can either appear on the 3rd beat of the first measure (like in Example 1) or on the 1st beat of the 2nd measure (Example 4).

• Sawaru: This is a softer attack of the thumb of the 4th beat on the first measure, using the standard upward motion. It is used with both patterns. Here is an example from the work Shukōshi in Sōjō (G mixolydian) mode with the shizugaki pattern.

• Ren: This is a glissando performed by the thumb, and it can be used with both patterns. It is most often used as a group of four 32nd notes on the up-beat of the 2nd beat of the 1st measure, leading to the 3rd beat as shown in the example.

• Musubute: This is a three measure pattern used only in three works: Bairo, Somakusha, and Manzairaku. The first measure of the pattern introduces a special technique of the thumb called kaeshizume.
• Kaeshizume: This is a sequence of attacks from underneath the strings by the thumb. This technique is not exclusive to the musubute pattern, and it can be used with the shizugaki and hayagaki patterns, in which case it appears as two eighth-notes on the 4th beat of the 1st measure.

Example 8 shows the basic melody of Etenraku's section B and C, and its rhythmic accompaniment. This shows in context how the koto uses its various patterns to color a melody. The phrase structure is of four measures of four beats, and each section is composed of two phrases. The piece is in Hyō-jō mode (E dorian) and the basic melody is centered on the pitches E, B, and A, which are three of the four fundamental pitches of the Japanese modal system.

Example 8 also shows the koto's standard two-measure motive, based exclusively on shizugaki + kozume. It is used to double certain melodic tones. As a point of clarification, the melodic tone supported in the first measure of the koto's pattern appears on the second beat of the measure. The pitch in the second measure of the koto's pattern doubles the melodic tone in rhythmic phase as in measure 6 and 12, and it can anticipate it as in measure 2, or follow it as in measure 14.

Note in measure 4 how the melodic tone 'E' is supported by a 'D' in the koto's part. We speculate that being half-way in the section, the purpose of this clash may be to avoid a too strong feeling of cadence on the 'tonic E' since one more phrase is needed to complete this section.

The excerpt is performed by the ensemble Reigakusha.

Non-metrical patterns

Typical unmeasured sections in kangen music include the netori and the 'coda' (the end of the piece). The netori is a very short piece played in free rhythm taht starts any performances of kangen. It allows the instruments to tune to the shō and adjust to the mode. The koto has two patterns that it uses exclusively in these sections:

Sugagaki: This pattern can be played in the coda or in the netori of the Taishiki-chō mode. Its melodic shape can be transposed on any pitches of the mode. It has several rhythmic variations including one where the four pitches all have the same duration.

Tsumu: This is a pattern used exclusively in the netori. Beyond that, it is exclusive to the modes that have scale degree 5 and 1 on their 5th and 7th strings, respectively. Consequently it is only used in the netori of the following modes: Hyō-jō, Taishiki-chō, Banshiki-chō, Sui-chō, and Oshiki-chō. The 5th and 7th strings are plucked together by the thumb and middle finger, with the hand positioned slightly away from the bridge, which produces a rather soft sound. The function of tsumu is to help with the tuning process of the netori, since the koto's sound is the most resonating of the two string instruments, and this pattern emphasizes the two most important pitches of a mode: its tonic and dominant.

Tsumu is always part of an unmeasured melodic/harmonic line. Example 10 shows a rhythmic and melodic approximation of a koto part for a netori in Oshiki-chō.