Portamentos, otherwise known as pitch bends or slides, are the technique of changing the pitch of strings while they are played. On guzheng this is accomplished by pressing the string on the left side of a movable bridge.
Pitch bending is an important part of Chinese music and its history. It reflects the importance of tones in Chinese languages and traces its lineage to chanted poetry and other vocal music. Each string can slide up to three half steps above its open pitch. For example, a string tuned to G can slide G -> G# -> A -> A#.
For the sake of these descriptions, every “press” means the left hand is pressing to the left of the movable bridges and a pluck is with the right hand to the right of the movable bridges.
The famous term is Huáyīn 滑音 or “Sliding Sound” which has its own entry below. There are more specific terms as well. These cover both single direction slides and multi-direction (back and forth) slides.
The general term for a pitch slide. Press a string with the left hand. Before or after that press, pluck the same string with the right hand.
The speed of the slide and its placement relative to the beat vary. To paraphrase from Kwok: If the slide comes before the principal pitch, the glide comes on the beat similar to a grace note. If the glide follows the principal pitch, it usually comes near or at the end of the indicated note duration.
Press a string to the required pitch, pluck the string, the relax the pressure to create a downward slide. May be abbreviated as Xiàhuá 下滑. Ferguson offers the variant Xiàhuá yǐ yīn 下滑倚音 (4) which translates to “Downward Appoggiatura”. It is used for faster rhythms, often as a grace note.
Ferguson also offers Qián huáyīn 前滑音 from Source C but doesn’t offer a description.
Pluck a string with the right hand then press it to create an upward slide to the desired pitch. May be abbreviated as Shàng huá 上滑. Ferguson offers the variant Shàng huá yǐ yīn 上滑倚音 “Upward Appoggiatura”. It’s an upwards huáyīn used for faster rhythms, often as a grace note.
Ferguson also offers Hòu huáyīn 后滑音 from Source C but does not offer a description.
Offered by Kwok, this is another term for a downward slide. Unclear how different this is from xiàhuá yīn.