The xiāo is a very ancient Chinese instrument usually thought to have developed from a simple end-blown flute used by the Qiang people of Southwest China. The modern six-hole form of the instrument goes back to the Ming Dynasty.
Xiao are today most often pitched in the key of G (with the D above middle C being the lowest note, with all fingers covered), although xiao in otherless common keys are also available, most commonly in the key of F. More traditional xiao have six finger holes, while most modern ones have eight; the additional holes do not extend the instrument's range but instead make it easier to play notes such as F natural. There are a further four (sometimes two or six) sound holes situated at the bottom third of the length of the xiao. The blowing hole is at the top end, it may be cut into a 'U' shape, a "V" shape, or at an angle (with or without bone/ivory inlay.) Some xiao have the blowing end entirely cut off, so the player must use the space between their chin and lips to cover the hole fully. There may be a metal joint between the blow hole and the top finger hole for tuning purposes and sometimes also between the last finger hole and the end. The length of the xiao ranges from around 45 cm to over 1.25 m but is usually around 75–85 cm. Usually, shorter xiaos are more difficult to play because of the need to control one's breath more accurately. The angle to play the xiao is around 45 degrees from the body.