The bawu (Traditional Chinese 巴烏, Simplified Chinese 巴乌) is a side-blown reedpipe found in Southern China, played by the Dai, Hani, Miao, Yi and other minorities. When in use it resembles a typical side-blown bamboo flute, but it has a triangular free reed made from brass set into the side of the pipe, surrounded by a mouthpiece (tradionally of bone, but these days comonly made of plastic):
This one is a fairly traditional model, having a thumb hole and six finger holes, plus a tuning hole. It has a range of just over an octave. Unlike the ala and ding tac ta, the pipe is closed at the upper end. It is made from two sections of bamboo and its overall tuning can be varied by adjusting the joint between the two pieces. This is a key of G instrument and plays the basic scale D E F# G A B D E:
Additional pitches can be played by underblowing, cross-fingering and/or half-holing and a G instrument would typically also be played in the keys of D, C and sometimes Bb, along with their relative minors.
In recent years, the rich, mellow tone of the bawu has become a favorite with composers of film soundtracks (the bawu was strongly featured in the score to "Crouching Tiger, Hidden Dragon") and many small Chinese music ensembles now feature a bawu player. "Improved" bawu have appeared over the last few decades, with drones, increased range, plastic construction, finger keys, etc. One of the most common variations on the traditional design is the double bawu (双管巴乌) which consists of a pair of bawu in different keys joined together so that their mouthpieces are in close proximity, allowing the player to switch quickly between them to play in a higher or lower register.
This bawu made by the Tian Yun Musical Instrument Co. is constructed entirely from synthetic materials:
Designed by Li Song, who holds numerous patents for bawu and hulusi designs, it features a considerably larger reed than usual and has keys to extend both the upper and lower ranges of the instrument. This one is on the key of F. A traditional bawu in F would play the scale C D E F G A C D, with a low A played by underblowing. The keys on this instrument allow low F G A and Bb to be played by underblowing and extend the upper range of the to include high E and F. There is also a key to give the Bb (on a traditional bawu the fourth of the scale has to be played by cross fingering or half-holing), giving the instrument a complete diatonic scale spanning two full octaves.
The keys also allow a variety of accidentals to be played.
Another common variation is the vertical bawu (竖巴乌 or 竖吹巴乌). These have a small windchest and are played in the upright position, resembling a simplified hulusi.
James Cottingham briefly discusses the physics of the bawu in his study The Asian Free Reed Mouth Organs.
A YouTube playlist devoted to the bawu.
If you are interested in learning to play the bawu (or the hulusi), may I humbly recommend my book How To Play Bawu and Hulusi, available from Createspace.com and Amazon.com
This is the first book in the English language to focus on these instruments and provides complete instruction for the absolute beginner. Includes background of the bawu and hulusi, advice on buying an instrument, basic and not-so-basic playing techniques, some familiar Western tunes to help you find your way around your instrument, a dozen traditional Chinese melodies, advice on care and maintenance, how to read JianPu (Chinese musical notation), fingering charts, recommended listening and more.
A Brief History of Mouth Blown Free Reed Instruments
What Is A Free Reed?
Origins Of The Free Reed
Eastern Free Reed Instruments
A Selective Discography Of Asian Free Reed Instruments
Western Free Reed Instruments
Bibliography