Curved flute - Kyokuteki

Japanese: 曲笛 - きょくてき

… Many of the important instruments in this third period are closely related to narrative music. First, the flute, which had been used as an accompaniment to narrative works since the Song Dynasty, became the “qufi” from the Yuan dynasty to the Kunqu dynasty, and played an important role in the high-pitched “bangfi” in bangzi music. In addition, during the Yuan dynasty, bowed string instruments that had originated in the Tang dynasty were transformed into kokyu, which used a bow made from horsetail instead of bamboo, and the sanxian also became popular, and from the mid-8th century, along with the biwa, which was played by hand and had more frets, became the main accompaniment for narrative works and opera music in the north and south. …

From 【Flute】

…After the Yuan Dynasty, the flute was used as a secular instrument to accompany dramas, and became the main instrument in the Kunqu (musical music) of the Ming Dynasty. Currently, it is also called the Dizi, and there are two types: the southern type called the Qiyoteki (called Qiyoteki because it was used in Kunqu) and the northern type called the Bangteki (bang flute). Both have six holes. …

*Some of the terminology that refers to "Kyubue" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…　この第3期の重要な楽器は，多く物語音楽と密接な関係がある。まず宋朝以来，語り物の伴奏として活躍していた笛は，元曲から崑曲に至って〈曲笛〉となり，梆子音楽でも高音の〈梆笛〉として重要な役割を果たした。それに，元朝には，唐朝に起こった擦弦楽器が，竹製から馬尾の弓を用いて胡弓となり，三弦も流行して，8世紀中葉より手で弾きフレットを増した琵琶とともに，南北の語り物や戯曲音楽の主要伴奏楽器となる。…