Seasoning (Gagaku) - Anbai

Japanese: 塩梅（雅楽） - あんばい

…The "flute" includes the hichiriki, various types of flutes, and the sho. The hichiriki is the most important instrument used in the most types of music, and is characterized by a playing style that uses a lot of portamento called "enbai," and plays the melody that forms the backbone of the piece at a loud volume. Currently, three types of flutes are used: the ryuteki, the koma-buke, and the kagura-buke, and their detailed and decorative sound movements make a good pair with the hichiriki. …

From 【Gagaku】

From "Hichiriki/Kokuriki"

...The pitch of the hichiriki can change considerably, even with the same fingering, depending on how the mouthpiece is held and how the breath is blown into it. The technique of "enbai," which smooths out the progression of a melody by continuously changing the pitch, can be said to have been born from the characteristics of this instrument. It is loud, but rich in expression. ...

*Some of the terminology explanations that refer to "Shiobai (Gagaku)" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…〈吹きもの〉には篳篥（ひちりき）と各種の笛，笙（しよう）がある。篳篥は最も多くの種目で用いられる重要な楽器で，〈塩梅（えんばい∥あんばい）〉というポルタメントの効いた奏法に特徴があり，大きな音量で曲の骨格となる旋律を奏する。笛は現在，竜笛（りゆうてき），高麗笛，神楽笛の3種が用いられており，細かく装飾的な音の動きは篳篥と好一対をなす。…