The koudi (Chinese: 口笛; pinyin: kǒudí; also spelled kou di) is a very small Chinese flute made from bamboo. It is the smallest flute in Chinese Flute family. Its original shape is from prehistorical instruments made with animal bone, while Koudi is made with wood, bamboo or PVC, which is very distinct with the original shape. It was invented in 1971 by dizi master Yu Xunfa (俞逊发, 1946–2006).
In 1971, the famous Chinese Flute player Yu Xunfa, who was inspired by original prehistorical instrument, made the first Koudi. This instrument contains one octave, and two years later this instrument went to public by playing the recomposed Romanian folk song Ciocârlia (《云雀》). After that, to expand the range,Xu made the five-hole Koudi, and Bai Chengren (白诚仁) composed Morning of A Miao Village《苗岭的早晨》(MaoLing de ZaoChen). Therefore, Koudi became famous in China. The instrument comes in two sizes. The smaller size, called gaoyin koudi, which is only 5–6 cm in length, has only the holes on the sides, where the thumbs can control the full range of pitch by incrementally opening the holes. The larger size, referred to as zhongyin koudi, is 8–9 cm long and has an additional 2–4 holes on the front (played with the fingers, these holes give slightly more precision to pitch changes). The gaoyin koudi is pitched an octave above the xiao di, whereas the zhongyin koudi is pitched an octave above the bang di. The range of the koudi is about a ninth or tenth, and it can bend notes over the entire range of the instrument.
Watching me fall
Into the flames
Of a broken soul tonight
No stone overturned
This graveyard of mine
Allows me no peace
[Chorus]
Sleep as day dies
Sleepwalk with the dead
Wander aimlessly through the night
Love and regret
Course through my veins
As I slowly fade away
Please let me sleep
Just one last night
Before I must wake
[Chorus]
And I walk with these ghosts
And I walk with these ghosts
And I walk with these ghosts...
[Chorus]
Sleep as night falls
Sleepwalk with the dead
Hope keeps me alive